6533b85ffe1ef96bd12c0f6f

RESEARCH PRODUCT

Consequences of linking charged and uncharged monomers to binary copolymers studied in dilute solution. Part II: Non-additivity effects in the viscometric behavior

subject

description

Abstract Copolymers of ethylene oxide (EO) and N,N-dimethyl aminoethyl methacrylate (R) or [2-(methacryloyloxy)ethyl] trimethylammonium iodide (R+) were studied in dilute solution: P ( EO p – b – R n ) ( I ) , P(Rn(1−f) – ran – R+n f) ( II ) , and P ( EO p – b – R n + ) ( III ) ; n and p give the numbers of monomers and f is the degree of charging. For II (variable f) and III (variable n) the effects of charging on the intrinsic viscosities [η] are well described by Boltzmann sigmoids. The deviation of [ η ] from [ η ] add (calculated from the corresponding homopolymer data, assuming additivity of the individual contributions) are quantified by σ = [ η ] / [ η ] add - 1 measuring the segregation ( σ > 0 ) or clustering ( σ 0 ) of dissimilar monomers in isolated coils. For II, σ changes from negative at low f to positive at high f. I and III pass maxima as n becomes larger, where σ is positive at low and negative at high n for I, but always larger than zero for III. The investigation of salt effects using NaCl, CaCl2 and NaI corroborates the observations for the homopolymers.