Startseite An investigation on thermo-mechanical performance of graphene-oxide-reinforced shape memory polymer
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An investigation on thermo-mechanical performance of graphene-oxide-reinforced shape memory polymer

  • Long Chen EMAIL logo , Qingbao Yang , Xue Yang , Zhanqiang Liu und Qinghua Song
Veröffentlicht/Copyright: 21. Juni 2022
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Abstract

Based on micro morphology, a thermo-mechanical coupling model of shape memory graphene oxide/epoxy resin (SMGO/EP) was proposed. The heat transfer capability, mechanical property and shape memory ability of shape memory polymer (SMP) were further investigated. The reliability of the modeling was verified by comparing the heat transfer and shape fixation rate of the experimental and simulation data. The results showed that the maximum error of heat transfer was 6.04%, and shape fixing rate error was 2.33%. When the volume fraction of GO was 1.50 vol%, the maximum stress can reach 158.39 MPa, 46.52% higher than that of pure shape memory EP. With the increase in the volume fraction of GO in the SMGO/EP composites, the heat transfer enhancement and recovery rate of SMGO/EP were directly affected by the doping content of GO. The surface temperature of the composites with GO doping content of 1.50 vol% was 20.26°C higher than that of pure SMEP after heating for 300 s. Under the coupling effect of heat transfer and stress characteristics, the mechanism of shape memory effect of SMGO/EP composites was revealed. The thermo-mechanical coupling modeling of SMGO/EP can effectively predict the shape memory characteristics of the SMGO/EP composites.

1 Introduction

Shape memory material (SMM) plays an important role in the field of intelligent materials. Its characteristic is that it has a certain initial shape, after deformation and fixed into another shape, it can sense the changes in specific external conditions (such as temperature, chemical, mechanical, optical, magnetic or electrical, and other external stimuli), so as to return to the initial state [1,2,3,4]. SMMs can be divided into shape memory alloy (SMA) [5,6,7,8,9], shape memory ceramic (SMC) [10,11,12,13], and shape memory polymer (SMP) [14,15,16,17,18,19,20]. Compared with SMA and SMC, SMP has the advantages of high shape recoverability (∼100%), stable shape fixity (more than 85%) and light weight (no more than 5 g/cm3) [21,22], so they become the main research direction of shape memory material in the future.

Many scholars have investigated the shape memory properties of shape memory epoxy resin (SMEP) [23,24,25]. Liu et al. [26] prepared the SMEP samples, and the results showed that the SMEP had high shape fixation rate (99.50%) and shape recovery rate (∼100%), and the glass transition temperature measured by differential scanning calorimetry was between 44.70 and 145.30°C. Wu et al. [27] successfully synthesized a new type of SMEP whose storage modulus ratio of the glassy state to the rubberized state was up to 400. After 6 test cycles, the shape fixity rate and shape recovery rate were maintained at about 99%. Sun et al. [28] prepared SMEP by two-stage curing method, and found that the exceptional shape memory properties of EP system can be maintained after the first stage curing. The tensile strength of the material can be effectively strengthened after the second stage curing.

However, the thermal stability, strength, and stiffness of pure shape memory polymer materials are relatively low, which greatly reduces the scope of its application [29,30,31,32,33]. For the sake of the better thermal and mechanical properties, relevant scholars try to enhance the mechanical strength and thermal stability of raw materials by adding some reinforced fillers, such as SiC [34], Fe3O4 [35], glass fiber [36,37], carbon fiber [38], carbon nanotubes (CNTs) [39,40], and graphene [41,42]. Compared with pure SMEP, the strength and Young’s modulus of CNTs/EP composite films prepared by Liu et al. were significantly improved [43]. Datta et al. [44] incorporated CNT film into SMEP to enhance shape memory CNT/SMEP composites. Compared with SMEP, the Young’s modulus of the shape memory CNT/SMEP composites increased by 52 and 514% at 25 and 50°C, respectively. The storage modulus also improved significantly and the increase range was between 60 and 82% in the range of 30–90°C. Wang et al. [45] prepared a novel ternary hybrid polymer shape memory composites composed of GO, CNTs, and waterborne epoxy resin (WEP). The data results indicated that GO and CNTs had synergistic effect on improving the thermal response speed, tensile strength, and thermal conductivity of the composites. It was the uniform dispersion of CNTs and the strengthening effect of GO that created the synergistic effect. Liu et al. [46] obtained SMEP composites (SMEPC) with excellent mechanical properties by introducing carbon fibers into pure SMEPC. The storage modulus of SMEPC is as high as 37 GPa at ambient temperature, and the maximum resilience is more than 4.40 GPa. Lu et al. studied the synergistic effect of self-assembled carboxylic acid-functionalized carbon nanotube (CNT) and carbon fiber [47], self-assembly multi-walled carbon nanotube (MWCNT) nanopaper and sub-micro nickle nanostrand [48] on the electrical properties and electro-active recovery behavior respectively. The vertically aligned nickel nanostrands will facilitate the heat transfer from the nanopaper to the underlying SMP composite to accelerate the electrical actuation. While the self-assembled carboxylic acid-functionalized CNTs and carbon fibers enable the SMP nanocomposites for Joule heating triggered shape recovery.

Graphene has exceptional properties in optics, electricity, and mechanics. It has important application prospects in materials science, micro-nano processing, and energy, because of which it is considered to be a revolutionary material in the future [49,50]. Yu et al. [51] studied the influence of GO content on epoxy polymer composites by doping different amounts of GO to SMEP. The results showed that when the mass fraction of GO was 0.80 wt%, the shape memory composites had extraordinary shape memory performance. Chen et al. [52] discussed the effect of thermally reduced graphite oxide (TrGO) content on the mechanical and thermal properties and shape memory behavior of TrGO/EP. The static mechanical tests showed that the addition of TrGO can significantly improve the Young’s modulus, tensile strength, flexural modulus, and flexural strength of EP. Comprehensively considering the mechanical properties and shape memory effect of TrGO/ESMP composite, the optimum TrGO content was 2 wt%. Wang et al. [53] prepared a novel thermoelectric response shape memory graphene/WEP composite. With the raise in the graphene content and temperature, the thermal active shape memory effect became better. The shape recovery rate of the composites was still more than 95% and the number of fold-unfold cycles had a small effect on the shape memory properties. Wang et al. [54] prepared a new type of rGO/EP/rGO sandwich structure composite film. The thermal response shape recovery process of the sample can be completed in only 3 s in hot water at 80°C. The above results show that the addition of rGO can optimize the performance of SMEP.

Simulating the shape memory process of materials by numerical simulation software has significant advantages in the in-depth study of thermo-mechanical coupling mechanism. Liu et al. [55] introduced in detail the integral hinge manufactured from carbon-fiber-reinforced SMEP, and obtained the elastic modulus of SMPC varying with temperature through tensile test. The results showed that the hinge had satisfactory shape memory recovery performance, including a 100% shape recovery rate after 10 fold-unfold cycles, and a shape recovery time of about 60 s from 180° to 0°. Based on the Neo-Hookean constitutive equation considering the time-temperature effect, Fan et al. established the tensile stress and strain expressions of thermal shape memory process [56]. The shape memory experiment was constructed by employing SMEP to calibrate the viscoelastic parameters, and the shape memory process under bending and torsion was successfully simulated to verify the reliability of the numerical method. Diani et al. [57] measured the viscoelastic behavior of SMEP and its correlation with time and temperature by dynamic mechanical analysis (DMA). The generalized Maxwell model was used to model the amorphous thermal solid under study. The viscoelastic behavior of the amorphous thermal solid was described by DMA experimental data and time-temperature superposition principle. The simulation results were in good accordance with the experimental data, which showed that the shape recovery time of amorphous polymer was related to temperature.

At present, most of the work only studied the shape memory properties of shape memory polymer composite, but the mechanism of the effect of GO doping on the thermal-mechanical coupling enhancement of SMEP has not been clarified. What’s more, the influence of GO doping on SMGO/EP’s heat transfer capability and mechanical property was also rarely mentioned. Therefore, based on the micro morphology characterization, a thermal-mechanical coupling numerical simulation model of SMGO/EP composite was established. The influence of shape memory performance of SMGO/EP composite with different volume fractions of GO was analyzed by finite element method. The relationship between shape memory effect and thermal properties of SMGO/EP was studied. The reliability of numerical simulation data was verified by experiments. Through the simulation results, the promotion of GO doping on heat transfer, mechanical properties and shape memory properties was hope to see.

2 Experimental setup

In this section, the principle and method of SMGO/EP composite preparation were introduced, and the cross section of SMGO/EP composite was characterized by scanning electron microscope (SEM). In addition, the verification experiment platform was set.

2.1 Materials

The materials used in this experiment included epoxy resin (E-51), provided by Shanghai Autun Chemical Technology Co., Ltd. GO was provided by Tanfeng Tech. Inc., with a lamellar diameter of 0.20–10 μm, layer number of 1–20, and a purity of ∼98%. The curing agent was employed as 4,4-Diaminodiphenylmethane (C13H14N2), which was purchased from Shanghai Zhanyun Chemical Co., Ltd. The dispersant was ethanol absolute (C2H6O), which was purchased from Wuxi Zhanwang Chemical Co., Ltd.

2.2 Preparation of SMGO/EP composites

The SMGO/EP composite sample in the experiment was composed of EP and GO. A certain quality of GO was weighed and dispersed in ethanol absolute for 15 min. The GO was mixed with preheated EP and then the mixture was uniformly dispersed for 30 min to prevent GO from agglomerating. The well-mixed mixture was put into the blast drying box and vacuum oven for 2 h, respectively, to remove the bubbles in the mixture. In this period, the carboxyl group of GO made the epoxy group ring open. Finally, the curing agent was added to the mixed liquids and stirred for about 10 min, and the mixed liquids was poured into the mold with dimension of 90 mm × 20 mm × 3 mm. The curing process was performed in a vacuum oven for 2.50 h at 80°C and 2 h at 150°C. The whole reaction process was shown in Figure 1. Red, blue and white spheres represented shape memory EP, GO and curing agent respectively After GO was mixed with shape memory EP, the oxygen-containing functional groups on the surface of GO will react with the groups of shape memory EP to form ester groups. Then the curing agent made the EP group ring open.

Figure 1 
                  Schematic of reaction mechanism during preparation of SMGO/EP composites.
Figure 1

Schematic of reaction mechanism during preparation of SMGO/EP composites.

2.3 Characterization

In order to characterize the microstructures of SMGO/EP composites, SEM (Hitachi SU-8010) was adopted. As can be seen in Figure 2, with the raise in GO doping content, the fracture cross-section of SMGO/EP composites became coarser, and the cross-linking between GO and EP became more complex. The GO lamellae were evenly dispersed in the EP matrix, and there was no fold or separation in the contact between GO and EP, indicating that GO and EP had good interfacial compatibility.

Figure 2 
                  SEM images of SMGO/EP composites with the GO content of (a) 0 vol%, (b) 0.5 vol%, (c) 1.0 vol%, and (d) 1.5 vol%.
Figure 2

SEM images of SMGO/EP composites with the GO content of (a) 0 vol%, (b) 0.5 vol%, (c) 1.0 vol%, and (d) 1.5 vol%.

2.4 Shape memory and heat transfer experiments

In order to verify the accuracy of the proposed simulation model, a SMGO/EP composite sample with volume fraction of 0.50 vol% of GO was prepared, and the experiment shown in Figure 3(a) was designed. During the deformation experiment, one end of the sample was horizontally fixed to the square table with a fixture, and the annular heating sleeve was fixed outside the sample to keep the sample temperature constant above the glass transition temperature (Figure 3[b]). The other end of the sample was slowly stretched at the speed of 0.50 mm/s through the electric push-pull meter to avoid breaking the sample due to large deformation. The maximum displacement of the push-pull meter was limited to 5 mm. After tensile deformation, the annular heating sleeve was removed to cool the sample to room temperature. The length of the sample was measured with a vernier caliper, and the shape fixation rate was calculated according to equation (10).

Figure 3 
                  Schematics of (a) shape memory process, (b) heat transfer experimental devices of shape memory process, (c) and (d) heat sensor arrangement.
Figure 3

Schematics of (a) shape memory process, (b) heat transfer experimental devices of shape memory process, (c) and (d) heat sensor arrangement.

During the recovery process, the sample was heated above the glass transition temperature (T g) to complete the thermal response shape memory recovery. The length of the sample was measured with a vernier caliper, whose accuracy was ±0.02 mm. During the measurement process, different positions of the sample were measured three times and the average value was taken to reduce the relative error of measurement. By comparing the experimental data with the simulation data, the error of the two groups of data was calculated to prove the reliability of the proposed modeling.

As shown in Figure 3(c), the prepared SMGO/EP composite sample was pasted on the heating pad with thermal conductive adhesive without gap between them. The heat flux of the heating pad was adjusted through the external power supply, and the upper surface of the sample exchanged heat with the air naturally. Three K-type thermocouples were employed to measure the temperature data of fixed points on the surface of the sample (Figure 3(d)). The average values were compared with the numerical simulation data. The thermocouple sensor had a temperature range of 200–400 K and accuracy of ±0.50 K, including uncertainty caused by data acquisition software. The thermocouple was pasted on the outer surface of the experimental sample with a thermal conductivity of 3.60 W/(m K) and a thickness of 0.15 mm. The heating pad was externally connected with DC power supply (MS605dD) with rated voltage of 60 V to provide the heating conditions required for the experiment. The maximum error between the experimental temperature data and the simulation data was calculated.

3 Micro finite element simulation

The calculation principle of finite element simulation process was proposed. The three-dimensional model was established according to the SEM characteristics. The parameter selection and boundary condition setting during modeling process were performed.

3.1 Modeling

The shape memory process of SMGO/EP composites is closely related to the constitutive model. Viscoelasticity is the model form of shape recovery characteristics of polymer materials. The shape memory behavior of shape memory polymer materials is essentially the viscoelastic behavior of polymers. It is assumed that GO is uniformly distributed in SMEP, and SMGO/EP composite is regarded as a kind of isotropic material.

The deformation behavior of SMEP was simulated by employing the generalized Maxwell constitutive mode. Considering the thermal expansion effect of the material, the linear viscoelastic constitutive model and the time temperature equivalent principle were used to calculate the deformation behavior of SMEP. The stress response of polymer viscoelasticity included viscosity and elasticity. The elastic part responded immediately under the action of force, while the viscous part appears slowly after relaxation time. For linear isotropic viscoelastic mechanics, the constitutive relation formula equation (1) and the stress function integral formula equation (2) of the foundation are as follows [58,59]:

(1) ε ̇ = 1 E σ ̇ + 1 η σ ,

(2) σ ( t ) = 0 t 2 G ( τ t ' ) e ̇ d t + I 0 t K ( τ t ) ϕ ̇ d t ,

where E and η represent the elastic modulus and viscosity of the material, respectively; e ̇ is the strain rate deviation of shear deformation; φ ̇ denotes the volume strain rate of volume deformation; K(t) is the bulk modulus relaxation function, and G(t) is the shear modulus relaxation function. K(t) and G(t) are functions of relaxation time τ. The relaxation time τ establishes the relationship with the actual time t by the following integral equation (3) and differential equation (4):

(3) τ = 0 t d t A T ( T ( t ) ) ,

(4) d τ d t = 1 A T ( T ( t ) ) ,

where T is the temperature and A T is the transfer function. The Williams–Landel–Ferry (WLF) equation is a commonly used form of transfer function, which is the instantaneous temperature equivalent equation. When applied to polymers, the glass transition temperature T g is usually used as the reference temperature. The specific form of WLF equation is shown as equation (5)[60], and the fitting results of relevant parameters in WLF equation are shown in Table 1.

(5) log A T = C 1 g ( T T g ) C 2 g + T T g ,

where C 1 g and C 2 g are constants of WLF equation, which is related to material. In the numerical simulation, the material has elastic deformation under the condition of T T g C 2 g .

Table 1

Fitting results of WLF parameters

Parameters T g C 1 g C 2 g
SMEP 100.00 17.44 51.60

In the numerical simulation, the K(t) and G(t) parameters describing the viscoelastic integral function are expressed in the form of Prony series. The values in Prony series are fitted by relaxation experiment, and the viscoelastic parameters are calculated by equations (6)–(9), as shown in Table 2.

(6) G ( t ) = G + i = 1 n G G i e t / τ i G ,

(7) K ( t ) = K + i = 1 n K K i e t / τ i K ,

(8) k _ i = K i K 0 ,

(9) g _ i = G i G 0 ,

where K and G denote the long-term bulk modulus and long-term shear modulus, respectively; τ i K and τ i G are the relaxation time of each Prony series. Usually, τ i K and τ i G are not equal, but it is assumed that τ i = τ i K = τ i G in the numerical simulation; k_i and g_i represent the relative bulk modulus and relative shear modulus, respectively. In Prony series, the order of bulk modulus n K and shear modulus n G may not be the same. In fact, it can be assumed that n K = 0 in the simulation.

Table 2

Fitting results of viscoelastic model parameters

SMEP g_i Prony tau_i Prony
1 0.86 0.1
2 0.07 1
3 0.05 10
4 0.005 100
5 0.003 1,000

SMGO/EP composite is a two-phase material, in which one is the homogeneous medium and the other represents a finite number of reinforced fillers [61]. The governing equation for the heat transfer analysis of the composite can be expressed as follows:

(10) ( ρ i c i ) T i τ = ( k i T i ) in Ω i ( i = 1 , 2 ) ,

where T i represents the average temperature, ρ i denotes the material density, c i represents the specific-heat, τ is the heat transfer time, k i is the coefficient of heat transfer, i = 1 refers to the GO, and i = 2 refers to the SMEP. For the SMGO/EP composite, additional equation is needed to define the temperature and heat flux at the interfaces between GO and SMEP, which can be expressed as follows:

(11) k i T i = h ( T 2 T 1 ) on Γ 12 ( i = 1 , 2 ) ,

(12) k i T i = h ( T 2 T 1 ) ( i = 1 , 2 ) .

where h denotes heat transfer coefficient indicating the interface thermal resistance when the heat is transferred from SMEP to GO.

The unit body taken from the SMGO/EP model can be considered as a thermodynamic system dV, as can be seen in Figure 4. The heat flow is transferred from bottom to top along the z direction. The heat retained in the system per unit time along the z direction is as follows [62]:

(13) Q z = ( q z q z + d z ) d x d y ,

where q z represents the input heat flux, q z+dz represents the output heat flux.

Figure 4 
                  Energy conservation of a unit.
Figure 4

Energy conservation of a unit.

The temperature field and heat flux are continuous in the SMGO/EP composite, and the equation can be written in the form of an expanded Taylor series at z, when the system dV tends to zero:

(14) q z + d z = q z + q z z d z .

The Fourier’s law is shown in equation (15). According to the equations (12)–(14), the energy generated inside the composite can be expressed as equation (16).

(15) q z = λ T z ,

(16) Q z = λ 2 T z 2 d z d x d y .

In the dV system, the increase in thermal energy per unit element is expressed as Q 1 and it can be calculated by equation (17). The heat transfers along the x, y direction are ignored, thus the heat transfer process can be approximated as one-dimensional heat conduction along z direction. There is no internal heat source inside the composite. Therefore, the heat conduction equation can be simplified as equation (18).

(17) Q 1 = ρ c T τ d x d y d z ,

(18) λ 2 T z 2 = ρ c T τ .

where λ is the thermal conductivity, ρ denotes the density, c represents the specific heat, t is the temperature, and τ is time.

For the natural convection heat transfer between the surface of SMGO/EP composite and the air, it follows Newton’s cooling formula, as can be seen in equation (19). The surface heat transfer coefficient is affected by many factors. In this example, the average surface heat transfer coefficient is set as 20 W/(m2 K) during the calculation.

(19) q = h ( t w t f ) .

where t w denotes the surface temperature, and t f represents the air temperature.

3.2 Simulation process

The prepared samples of SMGO/EP composites were characterized by micro electron microscope. According to the characterization results, the three-dimensional geometric model of EP matrix and randomly distributed GO were generated by Python script file, as shown in Figure 5. The length, width, and height of SMGO/EP composites are 90 × 20 × 3 μm3, respectively, and GO sheet with a diameter of ∼1 μm. Then the size of the model is enlarged by 1000 times to compare with the experiment of the actual sample. According to the micromorphology relationship, the contact relationship between GO and EP was established. Tie contact mode was selected under the interaction module to transfer stress and heat through nodes. According to the experimental measurement and calculation, the material parameters of EP and GO were as shown in Tables 3 5 [50] (Figure 6).

Figure 5 
                  Micro modeling of SMGO/EP composites.
Figure 5

Micro modeling of SMGO/EP composites.

Table 3

Thermophysical parameters of SMEP

Density (kg/m3) Specific heat (J/(kg K)) Conductivity (W/(m K)) Expansion coefficient (1/°C)
SMEP 1,500 530 0.363 6.470 × 10−5
Table 4

Mechanical parameters of SMEP at different temperatures

Temperature (°C) Young’s modulus (MPa) Poisson’s ratio
40 1792.50 0.36
70 586.40 0.39
80 261.20 0.41
100 34.90 0.43
Table 5

Thermophysical parameters of GO

Young’s modulus (GPa) Poisson’s ratio Density (kg/m3) Specific heat (J/(kg K)) Conductivity (W/(m K))
GO 1,050 0.1866 1,500 700 4,840
Figure 6 
                  Schematic of shape memory process: (1) stretch 5 mm above the glass transition temperature with a speed of 0.5 mm/s; (2) cool down at a speed of 0.9°C/s and maintain a strain of 5 mm; (3) remove the displacement load; and (4) heat at a speed of 0.9°C/s.
Figure 6

Schematic of shape memory process: (1) stretch 5 mm above the glass transition temperature with a speed of 0.5 mm/s; (2) cool down at a speed of 0.9°C/s and maintain a strain of 5 mm; (3) remove the displacement load; and (4) heat at a speed of 0.9°C/s.

The overall shape memory process of the SMGO/EP composites was as shown in Figure 6. First, the sample was heated to above the glass transition temperature (set as 120°C) to make the composites in a high elastic state. The sample was fixed one end and the other end was stretched 5 mm with a speed of 0.05 mm/s. Then, cooled down to 30°C with a speed of 0.9°C/s and kept for a period of time to fix the shape of the SMGO/EP composites. After the displacement load was removed, the sample was heated above the glass transition temperature with a speed of 0.9°C/s and returned to the initial state. The calculation formula equation (10) of the shape fixation rate R f and shape recovery rate R r are as follows, where L 1 denotes the initial length, L 2 represents the length after stretching, L 3 is the length after releasing, L 1 is the length of the SMGO/EP composites after shape recovery [63,64].

(20) R f = L 3 L 1 L 2 L 1 R r = L 2 L 1 L 2 L 1 .

3.3 Boundary condition and meshing

The stress–strain distribution of the shape memory process of the established model was calculated by visco analysis step. The setting of boundary conditions is shown in Figure 7(a). The grid element type of this process was eight node hexahedral linear reduction elements (C3D8R). The approximate global size was ∼1 mm, and the number of grids was 5,400. The heat transfer analysis step was employed to calculate the heat transfer of the model. By applying an external heat source with the size of 5,000 W/m2 on one side of the model, the boundary condition of the other side was heat transfer of natural convection. The boundary conditions were set as shown in Figure 7(b). The heat transfer analysis step was used to calculate the temperature field and heat flux distribution of the composite shape memory process. The grid element type adopted eight node heat transfer solid elements (DC3D8), the approximate global size was ∼1 mm, and the number of grids is 5,400. The schematic of mesh dividing is shown in Figure 7(c).

Figure 7 
                  (a) Displacement boundary conditions and temperature field, (b) heat transfer boundary conditions, and (c) meshing of modeling.
Figure 7

(a) Displacement boundary conditions and temperature field, (b) heat transfer boundary conditions, and (c) meshing of modeling.

4 Results and discussion

In this article, the correctness of the simulation results was verified by the experimental results. The shape memory performances, and thermal and mechanical properties of the SMGO/EP composites were studied by extracting the simulation data results.

4.1 Experimental validation

To verify the correctness of the simulation results, the SMGO/EP composite sample with a volume fraction of 0.50 vol% GO was prepared. The experiments shown in Figure 3 were performed, and the results were measured and shown in Table 6. After the displacement load was removed, the sample retracted 0.71 mm, the shape fixation rate of the composite was 85.80%, which was close to the shape fixation rate obtained by simulation (87.80%), and the relative error was only 2.33%. It was considered that the experimental results were reliable within the allowable error range. After reheating, it was observed and measured that the SMGO/EP composites basically returned to the initial state, and the shape recovery rate was 100%.

Table 6

Simulation and experimental comparison of shape memory characteristics

Retraction distance (mm) Shape fixation rate (%) Shape recovery rate (%)
Experimental 0.71 86.00 100
Simulation 0.61 87.80 99.99

Similarly, the prepared SMGO/EP composite samples with 0.50 vol% GO doping were tested for heat transfer characteristics. The experimental results are shown in Figure 8. The heating trend was consistent. The max relative error between the experimental and simulation values was the largest when heated to 15 s, and the max error was only 6.04%. The comparative data showed that the simulation error was within the allowable range, so that the simulation result was considered to be reliable.

Figure 8 
                  Comparison of experimental and simulation data.
Figure 8

Comparison of experimental and simulation data.

4.2 Shape memory performance

The mechanical properties of shape memory epoxy resin are closely related to temperature, thus the coupling relationship between stress, strain, and temperature must be considered in order to accurately and completely reflect the shape memory process of SMGO/EP composites.

As shown in Figure 9, the three-dimensional schematic diagram of the stress-strain-temperature relationship of shape memory epoxy resin was obtained through numerical simulation calculation. It can be seen that above the glass transition temperature (T g), the SMGO/EP composites were in a high elastic state. At this time, the elastic modulus was small, and the stress and strain in the tensile process were directly proportional, but the changes were not obvious. In state (a), the maximum difference of Mises stress was 0.90 MPa and the average stress was 1.66 MPa regardless of the stress concentration, as shown in Figure 9(a).

Figure 9 
                  Three-dimensional curve of stress-strain-temperature and (a) to (d) stress distribution at state (a) to (d) of stress-strain-temperature curve.
Figure 9

Three-dimensional curve of stress-strain-temperature and (a) to (d) stress distribution at state (a) to (d) of stress-strain-temperature curve.

As the temperature decreased below the glass transition temperature (T g), the stress increased significantly due to the increase in elastic modulus. In state (b) of the cooling period, the maximum difference of Mises stress increased to 25.82 MPa and the average stress was 38.10 MPa regardless of the stress concentration, as shown in Figure 9(b). At the moment after the displacement load was removed, the SMGO/EP composites rebounded and contracted with small displacement. During this period, the stress existed only where the stress was concentrated and the maximum Mises stress was only 1.45 MPa in state (c), as shown in Figure 9(c). In the subsequent heating process, the SMGO/EP composites were expanded by heating. When the sample was heated above the glass transition temperature, the composite quickly recovered its original shape. And the stress of the material was close to 0 in this period, as can be seen in Figure 9(d).

As can be seen from Figure 10(a), due to the same displacement load, the displacement changes in SMGO/EP composites with different graphene oxide contents were the same in the first 200 s. As can be seen from Figure 10(b), after 200 s, with the removal of displacement load, SMGO/EP composites with different GO contents had different degrees of displacement retraction (0.40–0.60 mm), and the size of retraction displacement determined the shape fixation rate of composites.

Figure 10 
                  Displacement-time relationship: (a) 0–300 s, (b) 180–220 s, and (c) 270–295 s.
Figure 10

Displacement-time relationship: (a) 0–300 s, (b) 180–220 s, and (c) 270–295 s.

After calculation, with the increase in GO volume fraction, the shape fixation rate of SMGO/EP composites increased from 87.80 to 90.56%. Only when the volume fraction of GO exceeded 1.50 vol%, the shape fixation rate of SMGO/EP composites was slightly higher than that of pure shape memory EP (90.34%). In addition, as can be seen from Figure 9 and (a) and 10(c), after 210 s, with the increase in temperature, the composite expanded by about 0.30 mm. After 280 s, it was heated above the glass state transition temperature, and the composite begins to recover its shape. The shape recovery rate gradually increased with the increase in GO content, and can finally return to the initial state. The shape recovery rates were close to 100%, which did not change with the change in GO content.

4.3 Mechanical property

In order to study the effect of GO doping on the mechanical properties of the SMGO/EP composites, the stress changes in shape memory process were obtained and explained.

Comparing the stress changes in the SMGO/EP composites with different volume fractions of GO in Figure 11, it can be seen that when the temperature was higher than T g, the doping content of GO did not reveal significant effect on the stress with the increase in strain. When no GO was added, the stress increased from 0 to 1.90 MPa, while the stress increased from 0 to 2.51 MPa under the condition of 1.50 vol% GO doping content.

Figure 11 
                  Stress distribution of SMGO/EP with different GO contents.
Figure 11

Stress distribution of SMGO/EP with different GO contents.

As the temperature gradually decreased below the glass transition temperature, the stress increased faster with the increase in the volume fraction of GO. When the temperature dropped to 30°C, the stress of pure shape memory EP was only 108.10 MPa. However, the stress of the sample with 0.50 vol% GO doping content was 133.18 MPa, which was increased by 23.20%. Compared with the samples with GO volume fraction of 1.00 vol% and 1.50 vol%, the stress of the samples was 144.60 MPa (increased by 33.77%) and 158.39 MPa (increased by 46.52%), respectively.

In the process of deformation, after removing the displacement load, the stress decreased instantaneously, but there was still a certain residual stress in the samples. As shown in Figure 11, the internal stress of SMEP was 3.63 Pa, while the internal stress generated by SMGO/EP composites was large. The internal stress of the sample with 0.50 vol% GO content was 24.60 MPa after removing the displacement load. The residual internal stress of the sample with GO volume fraction of 1.00 vol% was 35.48 MPa. When the volume fraction of GO was 1.50 vol%, the internal stress was 54.21 MPa. The above analysis showed that the internal stress of SMGO/EP composites increased with the increase in GO content after removing the displacement load. Then, in the recovery process, with the increase in temperature, the internal stress of SMGO/EP composites decreased linearly until the stress was completely eliminated. Furthermore, it can be obviously seen from Figure 10 that the attenuation rate of internal stress of SMGO/EP composite increased with the increase in the O content.

4.4 Heat transfer performance

In order to study the effect of GO doping on heat transfer process, the heat transfer process and results were analyzed. The contribution of GO to heat transfer enhancement was investigated.

Figure 12 shows the temperature distribution of SMGO/EP composites with 1.50 vol% GO content under the condition of heating for 60 s and heat source of 5,000 W/m2. As can be seen from Figure 12, the temperature of SMEP gradually decreased along the z-axis direction. The bottom temperature can reach 142.61°C, and the surface temperature was 114.74°C. It can be seen from the figure that the surface temperature of GO doping areas was high, and the maximum temperature can reach 125.58°C with remarkable heat transfer effect. The temperature without GO doping was only 114.32°C. The average surface temperature of SMGO/EP composites was 123.77°C after heating for 60 s, which was 9.03°C higher than that of pure SMEP.

Figure 12 
                  Comparison of temperature distribution of SMEP and SMGO/EP composites.
Figure 12

Comparison of temperature distribution of SMEP and SMGO/EP composites.

Figure 13 shows the section temperature distribution of SMGO/EP with different GO contents. The tagging positions in the cross section were randomly dispersed GO. It can be seen that the internal isotherms of the SMGO/EP composite were distributed in a curved shape, indicating that the temperature transfer was not uniform. The isotherm was obviously bent where the GO was distributed, accelerating the speed of heat transfer.

Figure 13 
                  Middle section temperature distribution of SMGO/EP composites with 0 vol%, 0.5 vol%, 1.0 vol%, and 1.5 vol% GO contents.
Figure 13

Middle section temperature distribution of SMGO/EP composites with 0 vol%, 0.5 vol%, 1.0 vol%, and 1.5 vol% GO contents.

As can be seen from Figure 14(a), under the condition of initial temperature (25°C) and the external heat source (5,000 W/m2), the surface temperature of the SMGO/EP composite increased linearly and then the temperature rise rate decreased gradually. After heating for 300 s, the heat transfer performance of the samples without GO doping was worst, and the average surface temperature was only 249.71°C. When the GO doping content was 0.50 vol%, 1.00 vol% and 1.50 vol%, the average surface temperature of the SMGO/EP composites corresponded to 259.42°C, 264.12°C and 269.97°C respectively.

Figure 14 
                  Temperature-rising curves with different GO contents: (a) 0–300 s, and (b) 0–60 s.
Figure 14

Temperature-rising curves with different GO contents: (a) 0–300 s, and (b) 0–60 s.

Furthermore, it can be seen from Figure 14(b) that after heating for 60 s, when the doping content of GO was less than 0.50 vol%, the heat transfer speed did not increase significantly. With the further increase of GO doping, the heat transfer rate of SMGO/EP composite increased from 1.91 to 2.16°C/s, which the heat transfer capacity increased by 13.09%. This is due to the GO has an ideal structure suitable for heat transfer, and all carbon atoms are fixed on one layer by covalent bonds. When some atoms in GO contact with the heat source and begin to vibrate, the vibration will be quickly transferred to the surrounding atoms through the strong force of covalent bonds. The heat is transferred from one position of GO to another [65]. In addition, graphene relies on a special phonon mode for heat conduction. Graphene has a strong covalent bond between carbon and carbon, a small mass of carbon atoms, a high phonon velocity, and the thermal conductivity is directly proportional to the phonon velocity, so the thermal conductivity is high. The existence of a large number of high-density polymers in GO/EP nanocomposites is also the reason for the enhancement of thermal properties [66].

5 Conclusion

In this article, the shape memory properties, heat transfer characteristics, and mechanical properties of GO-doped SMEP were investigated by numerical simulation. Based on the micromorphology, the thermo-mechanical coupling model of SMGO/EP composites was established. The reliability of the simulation results was verified by experiments. Through data comparison, the shape fixing rate error was 2.33%, and the shape recovery rate was close to 100%. In the process of heat transfer, the temperature rise trend of simulation and experiment was consistent, and the maximum error was 6.04%. By analyzing the simulation data, the following experimental conclusions were obtained:

  1. With the raising of the volume fraction of GO in the SMGO/EP composites, the maximum stress in the shape memory process increases accordingly. When the volume fraction of GO increases from 0 to 1.50 vol%, the maximum stress ranges from 108.10 MPa to 158.39 MPa; moreover, the stress of the SMGO/EP composites will not drop to 0 immediately after the displacement load was removed. The internal stress of the composites increases from 24.60 to 54.21 MPa with the GO doping from 0.50 to 1.50 vol% after the displacement load was removed. Moreover, the shape fixation rate of the SMGO/EP composites was directly proportional to the doping content of GO. When the volume fraction of GO was greater than 1.50 vol%, the shape fixation rate was greater than that of pure SMEP (90.34%). The doping of GO has small effect on the final shape recovery rate, which basically maintains 100% recovery. While, the shape recovery speed increased with the increase in the GO content.

  2. The doping of GO in SMGO/EP composites significantly improves the heat transfer efficiency of the composites and forms a local high heat conduction region in the materials. Furthermore, the surface temperature of the composites with GO doping content of 1.50 vol% was 20.26°C higher than that of pure SMEP after heating for 300 s, increasing from 249.71°C to 269.97°C. The heat transfer rate of the SMGO/EP composites was 13.09% higher than that of pure SMEP after heating for 60 s, increasing from 1.91°C/s to 2.16°C/s. The addition of GO optimized the heat transfer performance of the SMGO/EP composites. Due to the excellent heat transfer performance of GO, the shape fixation rate and shape memory recovery rate of SMGO/EP composites were improved.

  1. Funding information: This work was supported by Key Laboratory of Icing and Anti/De-icing of CARDC (Grant No. IADL20210407), Natural Science Foundation of Shandong Province (Grant No. ZR2019BEE068), and Natural Science Foundation of Guangdong Province (Grant No. 2020A1515111208). The authors thank the referees of this article for their valuable and very helpful comments.

  2. Author contributions: Long Chen: conceptualization, data curation, writing-review & editing, and methodology. Qingbao Yang: formal analysis and methodology. Xue Yang: writing-original draft. Zhanqiang Liu: formal analysis and methodology. Qinghua Song: data curation and writing-review & editing. All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  3. Conflict of interest: The authors state no conflict of interest.

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Received: 2022-03-14
Revised: 2022-05-09
Accepted: 2022-05-15
Published Online: 2022-06-21

© 2022 Long Chen et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

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  41. Thermally induced hex-graphene transitions in 2D carbon crystals
  42. The surface modification effect on the interfacial properties of glass fiber-reinforced epoxy: A molecular dynamics study
  43. Molecular dynamics study of deformation mechanism of interfacial microzone of Cu/Al2Cu/Al composites under tension
  44. Nanocolloid simulators of luminescent solar concentrator photovoltaic windows
  45. Compressive strength and anti-chloride ion penetration assessment of geopolymer mortar merging PVA fiber and nano-SiO2 using RBF–BP composite neural network
  46. Effect of 3-mercapto-1-propane sulfonate sulfonic acid and polyvinylpyrrolidone on the growth of cobalt pillar by electrodeposition
  47. Dynamics of convective slippery constraints on hybrid radiative Sutterby nanofluid flow by Galerkin finite element simulation
  48. Preparation of vanadium by the magnesiothermic self-propagating reduction and process control
  49. Microstructure-dependent photoelectrocatalytic activity of heterogeneous ZnO–ZnS nanosheets
  50. Cytotoxic and pro-inflammatory effects of molybdenum and tungsten disulphide on human bronchial cells
  51. Improving recycled aggregate concrete by compression casting and nano-silica
  52. Chemically reactive Maxwell nanoliquid flow by a stretching surface in the frames of Newtonian heating, nonlinear convection and radiative flux: Nanopolymer flow processing simulation
  53. Nonlinear dynamic and crack behaviors of carbon nanotubes-reinforced composites with various geometries
  54. Biosynthesis of copper oxide nanoparticles and its therapeutic efficacy against colon cancer
  55. Synthesis and characterization of smart stimuli-responsive herbal drug-encapsulated nanoniosome particles for efficient treatment of breast cancer
  56. Homotopic simulation for heat transport phenomenon of the Burgers nanofluids flow over a stretching cylinder with thermal convective and zero mass flux conditions
  57. Incorporation of copper and strontium ions in TiO2 nanotubes via dopamine to enhance hemocompatibility and cytocompatibility
  58. Mechanical, thermal, and barrier properties of starch films incorporated with chitosan nanoparticles
  59. Mechanical properties and microstructure of nano-strengthened recycled aggregate concrete
  60. Glucose-responsive nanogels efficiently maintain the stability and activity of therapeutic enzymes
  61. Tunning matrix rheology and mechanical performance of ultra-high performance concrete using cellulose nanofibers
  62. Flexible MXene/copper/cellulose nanofiber heat spreader films with enhanced thermal conductivity
  63. Promoted charge separation and specific surface area via interlacing of N-doped titanium dioxide nanotubes on carbon nitride nanosheets for photocatalytic degradation of Rhodamine B
  64. Elucidating the role of silicon dioxide and titanium dioxide nanoparticles in mitigating the disease of the eggplant caused by Phomopsis vexans, Ralstonia solanacearum, and root-knot nematode Meloidogyne incognita
  65. An implication of magnetic dipole in Carreau Yasuda liquid influenced by engine oil using ternary hybrid nanomaterial
  66. Robust synthesis of a composite phase of copper vanadium oxide with enhanced performance for durable aqueous Zn-ion batteries
  67. Tunning self-assembled phases of bovine serum albumin via hydrothermal process to synthesize novel functional hydrogel for skin protection against UVB
  68. A comparative experimental study on damping properties of epoxy nanocomposite beams reinforced with carbon nanotubes and graphene nanoplatelets
  69. Lightweight and hydrophobic Ni/GO/PVA composite aerogels for ultrahigh performance electromagnetic interference shielding
  70. Research on the auxetic behavior and mechanical properties of periodically rotating graphene nanostructures
  71. Repairing performances of novel cement mortar modified with graphene oxide and polyacrylate polymer
  72. Closed-loop recycling and fabrication of hydrophilic CNT films with high performance
  73. Design of thin-film configuration of SnO2–Ag2O composites for NO2 gas-sensing applications
  74. Study on stress distribution of SiC/Al composites based on microstructure models with microns and nanoparticles
  75. PVDF green nanofibers as potential carriers for improving self-healing and mechanical properties of carbon fiber/epoxy prepregs
  76. Osteogenesis capability of three-dimensionally printed poly(lactic acid)-halloysite nanotube scaffolds containing strontium ranelate
  77. Silver nanoparticles induce mitochondria-dependent apoptosis and late non-canonical autophagy in HT-29 colon cancer cells
  78. Preparation and bonding mechanisms of polymer/metal hybrid composite by nano molding technology
  79. Damage self-sensing and strain monitoring of glass-reinforced epoxy composite impregnated with graphene nanoplatelet and multiwalled carbon nanotubes
  80. Thermal analysis characterisation of solar-powered ship using Oldroyd hybrid nanofluids in parabolic trough solar collector: An optimal thermal application
  81. Pyrene-functionalized halloysite nanotubes for simultaneously detecting and separating Hg(ii) in aqueous media: A comprehensive comparison on interparticle and intraparticle excimers
  82. Fabrication of self-assembly CNT flexible film and its piezoresistive sensing behaviors
  83. Thermal valuation and entropy inspection of second-grade nanoscale fluid flow over a stretching surface by applying Koo–Kleinstreuer–Li relation
  84. Mechanical properties and microstructure of nano-SiO2 and basalt-fiber-reinforced recycled aggregate concrete
  85. Characterization and tribology performance of polyaniline-coated nanodiamond lubricant additives
  86. Combined impact of Marangoni convection and thermophoretic particle deposition on chemically reactive transport of nanofluid flow over a stretching surface
  87. Spark plasma extrusion of binder free hydroxyapatite powder
  88. An investigation on thermo-mechanical performance of graphene-oxide-reinforced shape memory polymer
  89. Effect of nanoadditives on the novel leather fiber/recycled poly(ethylene-vinyl-acetate) polymer composites for multifunctional applications: Fabrication, characterizations, and multiobjective optimization using central composite design
  90. Design selection for a hemispherical dimple core sandwich panel using hybrid multi-criteria decision-making methods
  91. Improving tensile strength and impact toughness of plasticized poly(lactic acid) biocomposites by incorporating nanofibrillated cellulose
  92. Green synthesis of spinel copper ferrite (CuFe2O4) nanoparticles and their toxicity
  93. The effect of TaC and NbC hybrid and mono-nanoparticles on AA2024 nanocomposites: Microstructure, strengthening, and artificial aging
  94. Excited-state geometry relaxation of pyrene-modified cellulose nanocrystals under UV-light excitation for detecting Fe3+
  95. Effect of CNTs and MEA on the creep of face-slab concrete at an early age
  96. Effect of deformation conditions on compression phase transformation of AZ31
  97. Application of MXene as a new generation of highly conductive coating materials for electromembrane-surrounded solid-phase microextraction
  98. A comparative study of the elasto-plastic properties for ceramic nanocomposites filled by graphene or graphene oxide nanoplates
  99. Encapsulation strategies for improving the biological behavior of CdS@ZIF-8 nanocomposites
  100. Biosynthesis of ZnO NPs from pumpkin seeds’ extract and elucidation of its anticancer potential against breast cancer
  101. Preliminary trials of the gold nanoparticles conjugated chrysin: An assessment of anti-oxidant, anti-microbial, and in vitro cytotoxic activities of a nanoformulated flavonoid
  102. Effect of micron-scale pores increased by nano-SiO2 sol modification on the strength of cement mortar
  103. Fractional simulations for thermal flow of hybrid nanofluid with aluminum oxide and titanium oxide nanoparticles with water and blood base fluids
  104. The effect of graphene nano-powder on the viscosity of water: An experimental study and artificial neural network modeling
  105. Development of a novel heat- and shear-resistant nano-silica gelling agent
  106. Characterization, biocompatibility and in vivo of nominal MnO2-containing wollastonite glass-ceramic
  107. Entropy production simulation of second-grade magnetic nanomaterials flowing across an expanding surface with viscidness dissipative flux
  108. Enhancement in structural, morphological, and optical properties of copper oxide for optoelectronic device applications
  109. Aptamer-functionalized chitosan-coated gold nanoparticle complex as a suitable targeted drug carrier for improved breast cancer treatment
  110. Performance and overall evaluation of nano-alumina-modified asphalt mixture
  111. Analysis of pure nanofluid (GO/engine oil) and hybrid nanofluid (GO–Fe3O4/engine oil): Novel thermal and magnetic features
  112. Synthesis of Ag@AgCl modified anatase/rutile/brookite mixed phase TiO2 and their photocatalytic property
  113. Mechanisms and influential variables on the abrasion resistance hydraulic concrete
  114. Synergistic reinforcement mechanism of basalt fiber/cellulose nanocrystals/polypropylene composites
  115. Achieving excellent oxidation resistance and mechanical properties of TiB2–B4C/carbon aerogel composites by quick-gelation and mechanical mixing
  116. Microwave-assisted sol–gel template-free synthesis and characterization of silica nanoparticles obtained from South African coal fly ash
  117. Pulsed laser-assisted synthesis of nano nickel(ii) oxide-anchored graphitic carbon nitride: Characterizations and their potential antibacterial/anti-biofilm applications
  118. Effects of nano-ZrSi2 on thermal stability of phenolic resin and thermal reusability of quartz–phenolic composites
  119. Benzaldehyde derivatives on tin electroplating as corrosion resistance for fabricating copper circuit
  120. Mechanical and heat transfer properties of 4D-printed shape memory graphene oxide/epoxy acrylate composites
  121. Coupling the vanadium-induced amorphous/crystalline NiFe2O4 with phosphide heterojunction toward active oxygen evolution reaction catalysts
  122. Graphene-oxide-reinforced cement composites mechanical and microstructural characteristics at elevated temperatures
  123. Gray correlation analysis of factors influencing compressive strength and durability of nano-SiO2 and PVA fiber reinforced geopolymer mortar
  124. Preparation of layered gradient Cu–Cr–Ti alloy with excellent mechanical properties, thermal stability, and electrical conductivity
  125. Recovery of Cr from chrome-containing leather wastes to develop aluminum-based composite material along with Al2O3 ceramic particles: An ingenious approach
  126. Mechanisms of the improved stiffness of flexible polymers under impact loading
  127. Anticancer potential of gold nanoparticles (AuNPs) using a battery of in vitro tests
  128. Review Articles
  129. Proposed approaches for coronaviruses elimination from wastewater: Membrane techniques and nanotechnology solutions
  130. Application of Pickering emulsion in oil drilling and production
  131. The contribution of microfluidics to the fight against tuberculosis
  132. Graphene-based biosensors for disease theranostics: Development, applications, and recent advancements
  133. Synthesis and encapsulation of iron oxide nanorods for application in magnetic hyperthermia and photothermal therapy
  134. Contemporary nano-architectured drugs and leads for ανβ3 integrin-based chemotherapy: Rationale and retrospect
  135. State-of-the-art review of fabrication, application, and mechanical properties of functionally graded porous nanocomposite materials
  136. Insights on magnetic spinel ferrites for targeted drug delivery and hyperthermia applications
  137. A review on heterogeneous oxidation of acetaminophen based on micro and nanoparticles catalyzed by different activators
  138. Early diagnosis of lung cancer using magnetic nanoparticles-integrated systems
  139. Advances in ZnO: Manipulation of defects for enhancing their technological potentials
  140. Efficacious nanomedicine track toward combating COVID-19
  141. A review of the design, processes, and properties of Mg-based composites
  142. Green synthesis of nanoparticles for varied applications: Green renewable resources and energy-efficient synthetic routes
  143. Two-dimensional nanomaterial-based polymer composites: Fundamentals and applications
  144. Recent progress and challenges in plasmonic nanomaterials
  145. Apoptotic cell-derived micro/nanosized extracellular vesicles in tissue regeneration
  146. Electronic noses based on metal oxide nanowires: A review
  147. Framework materials for supercapacitors
  148. An overview on the reproductive toxicity of graphene derivatives: Highlighting the importance
  149. Antibacterial nanomaterials: Upcoming hope to overcome antibiotic resistance crisis
  150. Research progress of carbon materials in the field of three-dimensional printing polymer nanocomposites
  151. A review of atomic layer deposition modelling and simulation methodologies: Density functional theory and molecular dynamics
  152. Recent advances in the preparation of PVDF-based piezoelectric materials
  153. Recent developments in tensile properties of friction welding of carbon fiber-reinforced composite: A review
  154. Comprehensive review of the properties of fly ash-based geopolymer with additive of nano-SiO2
  155. Perspectives in biopolymer/graphene-based composite application: Advances, challenges, and recommendations
  156. Graphene-based nanocomposite using new modeling molecular dynamic simulations for proposed neutralizing mechanism and real-time sensing of COVID-19
  157. Nanotechnology application on bamboo materials: A review
  158. Recent developments and future perspectives of biorenewable nanocomposites for advanced applications
  159. Nanostructured lipid carrier system: A compendium of their formulation development approaches, optimization strategies by quality by design, and recent applications in drug delivery
  160. 3D printing customized design of human bone tissue implant and its application
  161. Design, preparation, and functionalization of nanobiomaterials for enhanced efficacy in current and future biomedical applications
  162. A brief review of nanoparticles-doped PEDOT:PSS nanocomposite for OLED and OPV
  163. Nanotechnology interventions as a putative tool for the treatment of dental afflictions
  164. Recent advancements in metal–organic frameworks integrating quantum dots (QDs@MOF) and their potential applications
  165. A focused review of short electrospun nanofiber preparation techniques for composite reinforcement
  166. Microstructural characteristics and nano-modification of interfacial transition zone in concrete: A review
  167. Latest developments in the upconversion nanotechnology for the rapid detection of food safety: A review
  168. Strategic applications of nano-fertilizers for sustainable agriculture: Benefits and bottlenecks
  169. Molecular dynamics application of cocrystal energetic materials: A review
  170. Synthesis and application of nanometer hydroxyapatite in biomedicine
  171. Cutting-edge development in waste-recycled nanomaterials for energy storage and conversion applications
  172. Biological applications of ternary quantum dots: A review
  173. Nanotherapeutics for hydrogen sulfide-involved treatment: An emerging approach for cancer therapy
  174. Application of antibacterial nanoparticles in orthodontic materials
  175. Effect of natural-based biological hydrogels combined with growth factors on skin wound healing
  176. Nanozymes – A route to overcome microbial resistance: A viewpoint
  177. Recent developments and applications of smart nanoparticles in biomedicine
  178. Contemporary review on carbon nanotube (CNT) composites and their impact on multifarious applications
  179. Interfacial interactions and reinforcing mechanisms of cellulose and chitin nanomaterials and starch derivatives for cement and concrete strength and durability enhancement: A review
  180. Diamond-like carbon films for tribological modification of rubber
  181. Layered double hydroxides (LDHs) modified cement-based materials: A systematic review
  182. Recent research progress and advanced applications of silica/polymer nanocomposites
  183. Modeling of supramolecular biopolymers: Leading the in silico revolution of tissue engineering and nanomedicine
  184. Recent advances in perovskites-based optoelectronics
  185. Biogenic synthesis of palladium nanoparticles: New production methods and applications
  186. A comprehensive review of nanofluids with fractional derivatives: Modeling and application
  187. Electrospinning of marine polysaccharides: Processing and chemical aspects, challenges, and future prospects
  188. Electrohydrodynamic printing for demanding devices: A review of processing and applications
  189. Rapid Communications
  190. Structural material with designed thermal twist for a simple actuation
  191. Recent advances in photothermal materials for solar-driven crude oil adsorption
Heruntergeladen am 6.9.2025 von https://www.degruyterbrill.com/document/doi/10.1515/ntrev-2022-0133/html?lang=de
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