Synthesis And Characterization Of Thermosensitive Amphiphilic Helical Polymers Carrying Pnipam Pendants

Through molecular design, we made two new kind of macromolecule monomers:one monomer is propargylamine containing thermosensitive amphiphilic poly(N-isopropylacrylamide)(PNIPAM)(1B-2B), another one is propargylamine containing BOC-L-alanine(A). Then we synthesized copolymers by using the two kind of monomers mentioned above via (nbd)Rh+[n6-C6H5B-(C6H5)3] as catalyst. Moderate molecular weights (Mn)(3000-8300) of copolymers were measured by GPC. The optical activity and secondary structure of the copolymers were characterized by specific rotations ([(α]D) and circular dichroism (CD) spectra. The copolymers exhibited high optical activity in contrast to chiral monomer and formed single helical conformation.Internal and the external factors were observed on the second structure of copolymers.Certainly, the optical activity of copolymers increased with the increase of amino acids quantity growth. In addition, by adding the hydrophilic chain of PNIPAM, it provided the best driving force for self-assembly behavior. Amphiphilic self-assembled micelle were observed by CD, it showed that micelle still had optical activity. DLS showed that the grain size of micelle would be smaller with temperature rising.