Physico-chemical behaviour on molecular interactions of cationic surfactant with block copolymers at different temperature

Department of Physics, Pavai College of Technology, Pachal-637 018, Namakkal, Tamilnadu, India E-mail : panneer.phy@gmail.com PG Assistant in Physics, Government Higher Secondary School, Koothakudi-606 305, Villupuram, Tamilnadu, India The interaction of dodecyltrimethylammonium chloride (DTAC) with poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO) and poly(butylene oxide) (PBO) was studied by ultrasonic velocity measurements at 303 K and 323 K. Using the measured values of ultrasonic velocity, density and viscosity, the other related thermodynamic parameters such as adiabatic compressibility, intermolecular free length, internal pressure and acoustic impedance have been evaluated. These parameters have been utilized to study the strong solute-solvent interactions in these systems. A fairly good to excellent correlation between a given parameter and concentration is observed at all temperatures and solvent systems studied. The critical micellar concentration (CMC) is formed at 1.2 mM concentration in these systems. Linear or nonlinear increase or decrease in acoustical parameters with specific concentration and temperature indicate the existence of strong molecular interactions