The Internal Network Dynamics of Poly(NIPAM) Based Copolymer Micro- and Macrogels: A Comparative Neutron Spin-Echo Study
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Yvonne Hertle
Abstract
Microgels are generally synthesised above the lower critical solution temperature (LCST) of the used polymer (poly(N-isopropyl-acrylamide)(PNIPAM) in the present case) and there is evidence that, due to the “bad” solvent conditions and due to the differences in reactivity between the monomers and the crosslinker, an inhomogeneous crosslinker distribution in the network is created. In contrast, macrogels are statistically crosslinked, because they are polymerised below the LCST (good solvent conditions). With the neutron spin-echo (NSE) technique, the diffusion of the polymer network on a local length scale can be studied. Due to essentially different crosslinker distributions in the micro- and macrogels, a difference in the collective diffusion of the network could be expected. However, the measured intermediate scattering functions of the studied micro- and macrogel are similar and can both be described by a single exponential decay without a q-dependent baseline. Hence, both systems behave pseudo-ergodically on the length scale available in the NSE experiment. A determination of the diffusion coefficient of the breathing mode DG of the gel network and the dynamic correlation length ξ leads to comparable values for the homologous micro- and macrogels. The studied microgels contain butenoic acid as comonomer and also the pH dependence of the network dynamics is investigated.
©2014 Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Frontmatter
- Editorial
- Special Issue Commemorating the Paper “The Diffraction of X-rays by Crystals” by William Lawrence Bragg (ZPC, 104, 337–348 (1923); Nobel Lecture, September 6, 1922)
- Historical Paper
- The Diffraction of X-rays by Crystals
- Packing Effects of N-Ras Binding to a DOPC Membrane – a Neutron Reflectivity and TIRF Spectroscopy High-Pressure Study
- High Pressure X-ray Studies of Lipid Membranes and Lipid Phase Transitions
- Microscopic Structure Analysis in Disordered Materials using Anomalous X-ray Scattering
- Comparison of the Microstructure of Stimuli Responsive Zwitterionic PNIPAM-co-Sulfobetaine Microgels with PNIPAM Microgels and Classical Hard-Sphere Systems
- The Internal Network Dynamics of Poly(NIPAM) Based Copolymer Micro- and Macrogels: A Comparative Neutron Spin-Echo Study
- Configuration Determination of Transition Metal Complexes by Multiple Scattering EXAFS Analysis: A Case Study
- Review Article
- Ptychographic X-ray Microscopy with the Vacuum Imaging Apparatus HORST
- The Interaction of Bio-Molecules with Lipid Membranes Studied by X-ray Diffraction
- Deep Sea Microbes Probed by Incoherent Neutron Scattering Under High Hydrostatic Pressure
- X-ray Reflectometry and Related Surface Near X-ray Scattering Methods
Artikel in diesem Heft
- Frontmatter
- Editorial
- Special Issue Commemorating the Paper “The Diffraction of X-rays by Crystals” by William Lawrence Bragg (ZPC, 104, 337–348 (1923); Nobel Lecture, September 6, 1922)
- Historical Paper
- The Diffraction of X-rays by Crystals
- Packing Effects of N-Ras Binding to a DOPC Membrane – a Neutron Reflectivity and TIRF Spectroscopy High-Pressure Study
- High Pressure X-ray Studies of Lipid Membranes and Lipid Phase Transitions
- Microscopic Structure Analysis in Disordered Materials using Anomalous X-ray Scattering
- Comparison of the Microstructure of Stimuli Responsive Zwitterionic PNIPAM-co-Sulfobetaine Microgels with PNIPAM Microgels and Classical Hard-Sphere Systems
- The Internal Network Dynamics of Poly(NIPAM) Based Copolymer Micro- and Macrogels: A Comparative Neutron Spin-Echo Study
- Configuration Determination of Transition Metal Complexes by Multiple Scattering EXAFS Analysis: A Case Study
- Review Article
- Ptychographic X-ray Microscopy with the Vacuum Imaging Apparatus HORST
- The Interaction of Bio-Molecules with Lipid Membranes Studied by X-ray Diffraction
- Deep Sea Microbes Probed by Incoherent Neutron Scattering Under High Hydrostatic Pressure
- X-ray Reflectometry and Related Surface Near X-ray Scattering Methods
