Associative, thermodynamic and thermo-kinetics behavior of di- and triblock copolymers of oxyethylene and oxybutylene in aqueous media

• Associative, thermodynamic and thermo-kinetics behavior was investigated.
• Micellization of these copolymer is spontaneous, endothermic and entropy driven.
• Micelles are spherical in shape and their nature depends on temperature.
• Fusion/fission mechanism dominates over unimer entry/expulsion for micellar dynamics.
• Micellar parameters depend on temperature and on the delicate hydrophobic–hydrophilic balance of the blocks.

The associative, thermodynamic and thermo-kinetics properties of a diblock E90B10 and three triblock copolymers based on polyoxyethylene and polyoxybutylene of the type EmB10Em water have been studied by surface tensiometry, light scattering and temperature-jump stopped-flow techniques. The data from surface tension was helpful to detect the critical micelle concentration (CMC) as well as to calculate the thermodynamic parameters of micellization. Dynamic light scattering (DLS) was employed to obtain the values of hydrodynamic radii (Rh), volume (υh) and hydrodynamic expansion parameter (δh) of the micelle at different temperatures. Similarly, static light scattering (SLS) measurements made us enable to find out various micellar parameters such as; weight-average molar (Mw), association number (Nw), thermodynamic radius (Rt), thermodynamic volume (υt), anhydrous volume (υa) and thermodynamic expansion parameter (δt) of the micelles. Likewise, the kinetics of micellar aggregation/dynamic was also investigated by using temperature-jump stopped-flow technique in the temperature range of 20–50 °C.