Tailoring of stimuli-responsive water soluble acrylamide and methacrylamide polymers

The tailoring of the lower critical solution temperature (LCST) polymers of acrylamide and methacrylamide in water is achieved by chemical modificatio n of freely water soluble precursor polymers poly[N-2-hydroxypropylmethacry lamide], poly[N,N-bis(hydroxyethyl)acrylamide] and poly[N-(tris(hydroxymeth yl)-methyl)acrylamide]. Two principal reactions, namely acetylation and cin namoylation, are applied. By varying the acylating agent as well as the ext end of acylation, the LCST can be tailored easily. The cloud points observe d for the different polymer series do not correlate with the apparent hydro philicity of the parent polymers according to the content of hydroxyl group s. The results thus exemplify the difficulties to predict the behavior of m odified thermosensitive polymers by simply analysing the balance of hydroph ilic to hydrophobic molecular fragments. Chemical modification by cinnamoyl ation provides photoreactive copolymers e.g susceptible to photocrosslinkin g. When the polymers are prepared by polymerization using a disulfide-funct ionalized azo-initiator efficient grafting of the modified copolymers on go ld surfaces is possible to prepare ultrathin hydrogel films, as demonstrate d by Surface Plasmon Resonance.