Aligned porous stimuli-responsive hydrogels via directional freezing and frozen UV initiated polymerization

Abstract

Directional freezing and frozen UV initiated polymerization have been employed to prepare aligned porous stimuli-responsive hydrogels. Oligo-ethylene glycol methacrylates and dimethylamino ethyl methacrylate monomers are used to produce temperature and pH-responsive hydrogels respectively. The aqueous monomer mixtures are directionally frozen in liquid nitrogen and the frozen samples with dry ice are then polymerized by UV irradiation. Aligned porous morphologies are observed in both dry and hydrated states. The hydrogels exhibit stimuli-responsive behaviour in aqueous conditions and anisotropic compressive strength and diffusion behaviour with respect to freezing direction.