Characterization of Self-Association in Water of Polycations Hydrophobically Modified with Hydrocarbon and Siloxane Chains

Abstract

Terpolymers of quaternized N-(N‘,N‘-dimethylaminopropyl)acrylamide (DMAPAA), N-dodecylmethacrylamide (C12MAm), and a methacrylate substituted with a poly(dimethylsiloxane) chain of a degree of polymerization of 29 (Si29MA), Q/C12(x)/Si29(y), were synthesized by free radical terpolymerization. The self-association properties of these terpolymers were investigated in 0.1 M NaCl aqueous solutions in comparison with those of copolymers of quaternized DMAPAA with C12MAm (Q/C12(x)) or with Si29MA (Q/Si29(y)). In the terpolymers, the C12MAm contents (fC12 (i.e., x)) and Si29MA contents (fSi29 (i.e., y)) range from 3.6 to 26 and from 2.8 to 3.3 mol %, respectively, while in the Q/C12(x) and Q/Si29(y) reference copolymers, fC12 and fSi29 range from 7.4 to 31 and from 0.47 to 2.4 mol %, respectively. The following conclusions were drawn from experimental data by quasi-elastic light scattering, fluorescence, and 1H NMR (two-dimensional nuclear Overhauser enhancement spectroscopy and spin−lattice relaxation times) st...