Bilayer hydrogel assembly

The combination of two hydrogel layers based on photo-cross-linkable poly(dimethyl acrylamide) (PDMAAm) as base layer and poly(N-isopropyl acrylamide) (PNIPAAm) as top layer forms a bilayer assembly where, the base layer is highly swollen and the top layer shows temperature responsive swelling. Characterization was done by a combination of surface plasmon resonance spectroscopy and optical waveguide spectroscopy as well as atomic force microscopy. The PDMAAm and PNIPAAm within the bilayer assembly retain their swelling behavior, which they showed as a separate layer. Due to the presence of the photo-cross-linker such bilayer films can be patterned to develop surfaces with different properties at different regions.