Smart Polymer Hydrogels Based On Supramolecular Interactions

Polymer hydrogels are crosslinked networks that are composed of hydrophilic polymers,copolymers or polyelectrolytes.Due to the network structure and the hydrophilic nature,hydrogel usually contains a large amount of water and is able to response to many kinds of external stimuli such as temperature,p H,electric field,ionic strength and etc.Meanwhile,hydrogel is extremely similar with the materials forming living creatures,and this similarity endows hydrogel with great biocompatibility.As the extraordinary combination of stimuli-responsibility and biocompatibility,hydrogel possesses great potentials and shows promising potential applications in many fields like biomedical materials,biomimic materials and smart devices.In this thesis,we applied supramolecular chemistry in the fabrication of hydrogel and hydrogel system to improve their properties and expand their applications.The detailed contents are listed as follows:1.Poly[2-(N,N-dimethyl amino)ethyl methacrylate](PDMAEMA)brushes modified silica nanoparticles were used to fabricate nanocomposite hydrogel with poly(acrylic acid)(PAA)as the matrix.As the electrostatic interactions between PDMAEMA polycation and PAA ployanion,the prepared hydrogel possesses outstanding self-healing ability as well as robust mechanical property.This method offers a new way to solve the problem of the mechanical weakness in self-healing hydrogels.2.A double-layer structured hydrogel was fabricated combining poly(Nisopropylacrylamide)(PNIPAM)hydrogel with poly(acrylic acid-co-acrylamide)(PAAc/AAm)hydrogel.The two different hydrogen bonds with opposite thermal-responsibilities inside these two hydrogels endow the double-layer hydrogel with the ability to bend and unbend without external water supply,as water molecules can directional move inside the double layer structure.This design pushed the limit that hydrogel system can only actuate under water.