Self-assembly generation triggered in highly hydrophilic Pluronics® by sugars/ polyols

Abstract

Micellization and micellar morphology framed by polyoxyethylene (PEO)-polyoxypropylene (PPO)-polyoxyethylene (PEO)-based very hydrophilic triblock copolymers (BCPs) viz. Pluronics® F88 and F108 in aqueous solution and in presence of sugars is investigated from cloud point (CP) and scattering (DLS and SANS) studies. As not much is explored in this direction, the current study serves a novel approach giving a detailed description on the effect of sugars: monosaccharides (mannose, glucose, galactose), disaccharides (maltose, lactose, trehalose) and polyols (mannitol, sorbitol, inositol) in varying concentration on hydrophilic BCPs. These additives promoted micellization, decreased CP with a noticeable increase in the micelle core size which is due to the dehydration of the copolymer coil. The dynamic light scattering (DLS) results inferred the slight increase in hydrodynamic micellar size in the presence of sugars/ polyols that attribute to the interaction of sugars with BCPs. According to the study, the BCP micelles in the presence of these additives had much less water in both the core and corona domains. More precisely, the dehydration occurs more in the core region than in the corona region as depicted from small-angle neutron scattering (SANS). The relative sizes of the micellar core and corona altered by different sugars/ polyols depends on the degree of dehydration which followed the hierarchy: disaccharides > polyols > monosaccharides. A precise comprehension between the molecular orbital energies for the examined systems provide the perception of sugar-stabilized Pluronics® micelles from the evaluated optimum descriptors using Gaussian 09.