Ultrasonic velocity study of poly(R,R′,4,4′-cyclohexylidene diphenylene diphenyl ether-4,4′-disulfonate) solutions at 30, 35 and 40 °C

Ultrasonic velocity (2 MHz) and acoustic parameters of poly(R,R′-4,4′-cyclohexylidene diphenylene diphenyl ether-4,4′-disulfonate) (PS-1: RR′H; PS-2: RCH3 and R′H; PS-4: RCH3 and R′Cl) solutions (chloroform, 1,2-dichloroethane and tetrahydrofuran (THF)) at 30, 35 and 40 °C have been determined to understand the effect of methyl and chlorine substituents on molecular interactions to support solvophilic or solvophobic nature of the polymers. The linear increase of U, Z, R, b, π, (α/f2)Cl and τ with C and decrease of Ks, r, Lf and Vf with C suggested the existence of strong molecular interactions and hence solvophilic nature of the polymers, which is supported by positive values of Sn. A rise in temperature resulted in less ordered structure and more spacing between the molecules. The solvophilic nature of the polymers caused nonlinear variation of φv2 and φKs with C and T. A powerful solvation exists in THF system. Structural modification is found above 2% for PS-2 and PS-4. The decrease of Sn with C and T indicated the presence of polymer–polymer interactions. The decrease of Sn with T is due to disruption of the structure formed by predominant thermal energy over molecular interaction energy.