Polymer‐solvent interactions in mixed solvents, 1. Isotactic, syndiotactic and atactic poly(methacrylic acid) in water/2‐chloroethanol mixtures

The viscosimetric behaviour and the preferential solvation of syndiotactic, isotactic, and atactic poly(methacrylic acid), [poly(1‐carboxy‐1‐methylethylene)] are studied in water/2‐chloroethanol mixtures. The experimental results show that the preferential solvation of the polymer is strongly dependent on its local conformation. In the case of the syndiotactic sample, a close correlation has been established between the compact structure ↔ coil conformational transition and the variation of the preferential and absolute solvation of the polymer by 2‐chloroethanol, asserting the importance of hydrophobic interactions in the stabilization of the compact structure. Experimental data concerning the isotactic sample suggest the existence of an “inverse compact structure” in 2‐chloroethanol‐rich mixtures.