Association of copolymer acrylic acid/methyl-acrylic acid/butyl acrylate in aqueous solution

The associations of triblock copolymer made of acrylic acid, methyl-acrylic acid and butyl acrylate in aqueous solution as well as in NaCl and CaCl2 S olutions were studied by using fluorescence. The micelle-like clusters (MLC s) of copolymer formed is able to solubilize non-polar material. A little e lectrolytes added in the copolymer solution can increase the value of criti cal aggregation concentration (rho (ac)) and micropolarity. But with the in crease of the concentration of electrolytes, the value of p(ac) and micropo larity will decrease. When there is NaCl with fixed concentration in the sy stems, the process of the MLCs loosening is relaxed because of the charge-s creening. In the systems with fixed CaCl2 concentration, Ca2+ induced the c ross-link of -COO- groups, so the interface between the MLCs and the water is not obvious and the big MLCs is formed between the clusters.