Synthesis And Properties Of The Functional Poly(4-vinylpyridine)

In this paper, 1) the photo-sensitive telechelic poly(4-vinylpyridine) (C-P4VP), 2) modified poly(4-vinylpyridine) polymers (P4VP-PEO, P4VP-OPD), 3) the ammonium salt containing amphiphilic alternating polymers P(TMVPMA-alt-OPD) and P(VBDBA-alt-OPD) were synthesized by free radical polymerization. All polymers were characterized with 1H-NMR, GPC and FTIR, and the self-assembly of them were respectively researched.1) The novel photo-sensitive telechelic polymer (C-P4VP) was prepared with 4-vinylpyridine, using coumarin-containing disulfides (C-S-S-C) as a chain transfer agent in the presence of tributylphosphine and water. It was found that the telechelic polymer can form the micelles in the aqueous solutions at various pH values (pH = 3-6). Moreover, lowering the pH of the aqueous polymer solution, the polymer micelles gradually transferred into the compact morphology, and the photo-dimerization of coumarin group increased relatively within the same irradiation time.2) The crosslinked poly(4-vinylpyridine) (P4VP) was prepared by the copolymerization a styrene monomer containing disulfide bond (St-S-S-St) and 4-vinylpyridine. Then the internal disulfide bond was cleaved to thiol by reduction with tributylphosphine/water, and the"Thiol-ene"reaction happened between the thiol and the monomer of PEO or OPD, resulting in the P4VP-PEO and P4VP-OPD, respectively. It was found that both polymers can form the micelles in the aqueous solutions at various pH values. Moreover, as the pH of the aqueous solution got higher, the micelles of P4VP-PEO became bigger with the more compact morphology; while P4VP-OPD formed micelles at pH = 4.77, with a dispersion structure on the surface.3) The alternating polymer P(CMS-alt-OPD) was prepared by N-(n-Octyl) maleimide (OPD) and p-(chloromethyl) styrene (CMS) through free-radical polymerization. Then the P(CMS-alt-OPD) was used to prepare ammonium salt amphiphilic P(TMVPMA-alt-OPD) and P(VBDBA-alt-OPD) with trimethylamine and tri-n-butylamine, respectively, and the amphiphilic properties of these polymers can also be adjusted by the change of counter ions. Their self-assembly and emulsification were characterized by Malvern Nano ZS ZEN3600 instrument or dynamic laser scattering (DLS) and transmission electron microscopy (TEM). It was found that all the polymers can form micelles in aqueous solutions, and the average diameter decreased along with the hydrophobic enhancement of polymers. And the emulsion experiment showed that the more hydrophobic the polymer, the more stable the emulsion solution.