Disentangling Polymer Network and Hydration Water Dynamics in Polyhydroxyethyl Methacrylate Physical and Chemical Hydrogels

Published

August 8, 2019

Author(s)

Daria Noferini, Antonio Faraone, Marta Rossi, Eugene Mamontov, Emiliano Fratini, Piero Baglioni

Abstract

Cross-linker nature and water content may impact the microscopic dynamics of hydrogels components, and thus their properties in applications such as drug-delivery. To investigate this aspect, we used quasi-elastic neutron scattering with contrast variation to distinctly study the polymer and water dynamics in polyhydroxyethylmethacrylate (pHEMA) chemical (cg) and physical (pg) hydrogels with different water content. For the polymer network, a distribution of relaxation processes was observed, mainly related to the side-chains. Water dynamics was found to occur as H-bond governed process with jump diffusion mechanism. The interaction with the polymer matrix considerably slows the water dynamics with respect to bulk water and other confined systems and leads to a fraction of water molecules appearing as immobile. With higher hydration level, the mobility of both the water and the polymer network increases. For the same water content, pg networks present slower relaxation processes and smaller explored space than their cg equivalents as a result of side-chains involvement in the formation of the 3D network. The water mobility is sensibly reduced in the cg compared with pg in the less hydrated gels, whereas at higher hydration the values are similar but with shorter residence times in cg.

Citation

Journal of Physical Chemistry C

Volume

123

Issue

31

Pub Type

Journals

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Citation

Noferini, D. , Faraone, A. , Rossi, M. , Mamontov, E. , Fratini, E. and Baglioni, P. (2019), Disentangling Polymer Network and Hydration Water Dynamics in Polyhydroxyethyl Methacrylate Physical and Chemical Hydrogels, Journal of Physical Chemistry C, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=927751 (Accessed December 2, 2024)