Preparation of uniformly sized interpenetrating polymer network polyelectrolyte hydrogel droplets from a solid-state liquid crystal shell

[Display omitted] •LCsolid shell templates prepared by a microfluidic method with reactive mesogen mixtures were used for production of the hydrogel droplets.•Anionic, cationic, and zwitterionic IPN polyelectrolyte hydrogels were successfully produced by the LCsolid shell templates.•Anionic IPN droplets were applied to a Ca2+ sensor by monitoring the speed at which the size of the droplet reduced.•Polyelectrolyte IPN hydrogel droplets showed selective adsorption of the oppositely charged materials. Uniformly sized interpenetrating polymer network (IPN) polyelectrolyte hydrogel droplets were produced with solid-state liquid crystal (LCsolid) shells, which had been produced by a microfluidic method. The weak polyelectrolyte hydrogel and the temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) networks were intertwined in the LCsolid shell to produce an IPN structure; the anionic poly(acrylic acid) (PAA) and cationic poly(N-[3-(dimethylamino)propyl] methacrylamide) (PDMAPMA) were utilized for the weak polyelectrolyte hydrogel networks. The anionic PNIPAM/PAA, cationic PNIPAM/PDMAPMA, and zwitterionic PAA/PDMAPMA IPN droplets were successfully produced by the LCsolid shell templates. The PNIPAM/PAA IPN droplets were applied to a Ca2+ sensor. Further, the anionic PNIPAM/PAA and cationic PNIPAM/PDMAPMA IPN droplets could adsorb the cationic methylene blue and anionic Acid Red 37 dyes, respectively, while the zwitterionic PAA/PDMAPMA IPN droplets could adsorb both dyes. This method of producing uniformly sized IPN hydrogel droplets from LCsolid shell templates is simple and does not require any sophisticated machines.