Polymer gradient networks (PGN) play crucial role in the development of functional coatings for various biological applications (e.g., tissue engineering). PGN exhibit position-dependent continuous variation of network modulus on a flat solid support. We have developed a novel strategy to generate surface-attached PGN with tunable stiffness by copolymerizing acrylamides with 5% of methacryloyloxybenzophenone (photo-activable) and styrenesulfonylazide (thermally-activable) crosslinkers. The incorporation of thermal and photo crosslinkers allows for complete control over the crosskink density in an orthogonal fashion (i.e., light vs. heat). The effect of crosslink density on wettability and swelling was studied. The tensile modulus (E) and mesh size of swollen networks were determined using modified Flory-Rhenar model. It was found that increasing the crosslink density resulted in stiffer (i.e. high modulus) materials. The results of swelling, mesh size and modulus of the PGN were correlated with protein adsorption on the PGN substrate.Figure 1: (A) Photographs of poly(N-isopropylacrylamide) gradient networks. (B) Graph shows the film thickness as a function of photo energy dosage (J/cm2) used for photo crosslinking. The film thickness was found to increase with increasing UV light energy.

Surface-attached polymer gradient networks

248th National Meeting (2014)

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