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Molecular motions in low cross-linked poly(N-isopropylacrylamide) microgels |
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| Authors: | J Rubio-Retama B Frick Tilo Seydel B Lpez-Ruiz A Fernandez-Barbero E Lpez-Cabarcos |
| Institution: | aDepartment of Pharmaceutical Chemical-Physics, University Complutense of Madrid, 28040 Madrid, Spain bInstitut Laue Langevin, Grenoble, France cDepartment of Analytical Chemistry, University Complutense of Madrid, 28040 Madrid, Spain dComplex Fluid Physics Group, Department of Applied Physics, University of Almeria, Cañada de San Urbano s/n, E-04120 Almería, Spain |
| Abstract: | Non-ionic N-isopropylacrylamide (PNIPAM) microgel is employed to investigate the molecular motion of polymer chains in the swollen and collapsed states. This study is performed using incoherent elastic (IES) and quasielastic neutron scattering (IQNS). IES measurements show an increase of both, the elastic intensity and the oscillations of the polymer network vibrational amplitude at the transition temperature. IQNS was measured at two different selected temperatures 290 K and 327 K corresponding to the swollen and collapsed states, respectively. The diffusion constant from IQNS experiments decreases nearly two orders of magnitude when the microgel de-swells and finally collapses. |
| Keywords: | Microgels Molecular dynamics Neutron scattering Volume phase transition PNIPAM |
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