FABRICATION AND PROPERTIES OF THERMO-SENSITIVE ORGANIC/INORGANIC HYBRID HYDROGEL THIN FILMS

摘要

@@Stimuli responsive hydrogels have been extensively investigated due to their potential applications as controllable switches, controlled drug release materials, adsorbents, and sensors, etc. An important family of stimuli-responsive hydrogels are the derivatives of poly(N-isopropylacrylamide) (PNIPAm). PNIPAm exhibits a low critical solution temperature (LCST) at～32 °C. PNIPAm is hydrophilic and soluble in aqueous solution below its LCST, whereas it becomes hydrophobic and insoluble, above. From a technical viewpoint, applications of the hydrogels require a fast response to external stimuli. to achieve this, the reduction of the hydrogel size is a promissing approach since the response rate is inversely proportional to the square of the characteristic dimension of the hydrogel. Along this line, nano- or micro-sized hydrogel particles and hydrogel thin films were prepared. Several methods have been developed for fabricating hydrogel thin films, which are as photo-cross-linking by UV light, electron beam irradiation, plasma polymerization, and electrochemical polymerization.