Epidermis-Inspired Porous Polymer Films Grown in situ from Hydrogel Surfaces

The outmost layer of skin epidermis comprises of nanostructured corneocytes embedded in extracellular lipid matrix that endows the epidermis with permeative and protective properties. Inspired by such structure, here we produced multifunctional porous polymer films on hydrogels by a simple yet robust in situ interfacial precipitation polymerization of specific water-soluble monomers that become insoluble as they polymerize. This was applied on diverse hydrogel substrates, yielding unusually durable interfaces which exhibited epidermis-like characteristics. For example, the polymer films possess a thickness of 20 to 330 µm and comprise of interconnected nanoparticles tightly bonded to hydrogel surfaces, which structurally resemble the layer of interlocked corneocytes in the epidermis. Due to these unique structural features, the film exhibits an excellent permeability towards small molecules in the first instance but can then be tailored towards effective protection from excess water loss and for enhanced electrical resistivity. These polymer films provide a platform for the development of engineered materials for diverse applications.