Polyacrylonitrile-block-poly(methyl acrylate)(P(AN-b-MA)) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization employing macro-RAFT agent (PAN-RAFT) as the chain transfer agent and azobis(isobutyronitrile) (AIBN) as the initiator. A linear relationship between ln([M]0/[M]t) and reaction time was observed. The molecular structure of P(AN-b-MA) was characterized by 1H-NMR, element analysis, FTIR and SEC. The molecular weight distribution (MWD) was less than 1.40, the Mn could be controled from 0.733 to 4.834×104, and the molar content of MA in P(AN-b-MA) were from 15.6 to 75.0 percentage, respectively.
The adsorption amount of poly(styrene sulfonate) and poly(dimethyldiallyl ammonium chloride) (PSS/PDDA) self-assembled multilayer membranes in designed dipping solvents were measured by UV-Vis-spectroscopy and quartz crystal microhalance (QCM). Intrinsic viscosities of PSS and PDDA in corresponding dipping solvents were determined by an Ubbelohde viscometer. It is found that the adsorption amount of PSS/PDDA self-assembled multilayer membranes built up in different dipping solutions, added salt concentration, pH of solution and solvent quality, respectively changed oppositely with the corresponding intrinsic viscosity of PSS and PDDA in dipping solvents. A negative relation between the adsorption amount and intrinsic viscosity was revealed, and explained in term of the concept of excluded volume of polymer molecule in dilute solutions.
UV absorbance(A) of self-assembled films of poly(dimethyldiallyl ammonium chloride)(PDDA) and poly(styrene sulfonate)(PSS) with various concentrations of polyelectrolyte(c__P) at different concentrations of sodium chloride was investigated. It was found that the A～c__P curves display a discontinuous phenomenon. And the turning point concentration, at which the A～c__P curve starts to display a discontinuous phenomenon, is in good agreement with the critical concentration c* of PSS or PDDA polyelectrolyte solutions. The results above attribute to the change of chain shape of polyelectrolytes in solutions caused by c__P and c(NaCl). Thus, it is inferred that chain shape of polyelectrolyte in solutions affects the thickness of PSS/PDDA multilayer films.
