Tunable Sugar-Solanesol Block Copolymer Wormlike Micelles for Pickering-like Emulsions.

Abstract

A general design framework for fully bio-based block copolymers that integrates structural organization with macroscopic function remains largely unexplored, despite extensive study of amphiphilic systems. Herein, we address this challenge by designing fully bio-based diblock copolymers (i.e., Glc6/7-b-Sol) comprising hydrophilic maltooligosaccharide blocks predominantly composed of maltohexaose/maltoheptaose (Glc6/7) units and hydrophobic, plant-derived solanesol blocks. These copolymers form amphiphilic assemblies that integrate concentration-dependent viscoelasticity, mechanical responsiveness, and oil-water interfacial stabilization. The copolymer self-assembles into ultra-high-aspect-ratio (≈1200) wormlike micelles in water, each with a solanesyl core and sugar corona. Small-angle X-ray scattering experiments revealed significant inter-worm correlations at high concentrations, whereas the micellar cross-sectional diameter remained unchanged. Rheological measurements revealed strong concentration-dependent viscoelasticity at 40 g L-1, with a solution-to-gel-like transition affording elastic-dominated behavior, pronounced shear thinning, and full thixotropic recovery following repeated deformation at 1000% strain. The wormlike micelle rapidly fragmented into shorter segments when probe-sonicated, followed by partial reassembly of its length. The mechanically fragmented assemblies formed via sonication in the presence of oil were found to stabilize n-dodecane-in-water Pickering-like emulsions. The optimal 10 vol % n-dodecane-containing formulation afforded oil droplets with a mean diameter of 213 ± 10 nm that showed long-term stability for over 17 d. These findings establish mechanically reversible, fully bio-based wormlike micelles with tunable viscoelasticities as sustainable, surfactant-free platform materials for food, pharmaceutical, and material formulations.