Thermal and scattering studies of Tetronic^® 1304 micelles in the presence of industrially important glycols, their oligomers, cellosolves, carbitols, ethers and esters

Abstract

© 2016 Elsevier B.V. The influence of different glycol additives on the phase behaviour and micellar characteristics of a moderately hydrophobic ethylene oxide-propylene oxide(EO-PO) star block copolymer Tetronic®1304 (hereafter written as T1304) has been investigated by cloud point (CP), viscosity, high sensitivity differential scanning calorimetry (HSDSC), dynamic light scattering (DLS) and small angle neutron scattering (SANS). Glycol additives are commonly used in several industrial and pharmaceutical applications in the presence of these biocompatible, linear and branched EO-PO block copolymers functioning as dispersants, emulsifiers, detergents, defoaming agents and vehicles in pharmaceutical applications. Hence, it is essential to understand the behavior of star block copolymers in their presence (glycol additives) to optimize the performance for applications in diverse areas. In the case of short chain glycols/ethers/cyclic ethers an increase in CP, critical micelle temperature (CMT), hydrodynamic diameter (Dh) has been observed while aggregation number (Nagg) and relative viscosity decreases indicating demicellization. On the other hand, the long chain glycol ethers/aryl ethers/esters promote micellization with an increase in Nagg, micelle size, relative viscosity and decreased CMT. The influence on the micellar characteristics of T1304 is mainly dominated by the hydrophobicity and locus of solubilization of the glycol additives. The morphology of the star block copolymers can thus be customized using different glycol additives for particular applications. The information from this work will be highly lucrative for the industrial and therapeutic applications of star block copolymers using commonly used glycols to optimize their performance.