Investigation of the hydration kinetics of novel poly(ethylene oxide) containing polyurethanes

We report on the study of the hydration of a series of poly(ether urethanes) of varying poly(ethylene oxide) content within their soft segments using surface plasmon resonance (SPR). The study of the extent and dynamics of polymer film swelling upon hydration by SPR reveals that the technique is sensitive to the influence of polymer composition (soft segment and chain extender) of the polyurethane which are known to control polymer hydration. SPR analysis has been able to monitor the kinetics of these structural changes in situ, showing rapid initial hydration which appears to slow in an exponential fashion with time. The observed changes in surface elasticity of the polyurethane films on hydration were also confirmed by force-distance atomic force microscopy data. These data revealed a change in surface compliance which mirrored the measured modification in the surface refractive index as measured by SPR. These findings are discussed in the context of the polyurethane surface structure and the potential future use for screening hydration of such polymers is highlighted.