Self-Propelling Hybrid Gels Incorporating an Active Self-Assembled Low-Molecular-Weight Gelator

Hybrid gel beads based on combining a low-molecular-weight gelator (LMWG) with a polymer gelator (PG) demonstrate enhanced ability to self-propel in water, with the LMWG playing an active role. Hybrid gel beads were loaded with ethanol and shown to move in water via ‘Marangoni effect’ surface tension changes caused by the expulsion of ethanol – smaller beads move further and faster than larger beads. Flat shapes of the hybrid gel were cut using a ‘stamp’ – circles moved the furthest while stars showed more rotational movement on their own axis. Comparing hybrid LMWG/PG gel beads with PG-only beads demonstrated that the LMWG speeds up the beads, enhancing the rate of self-propulsion. Self-assembly of the LMWG into a ‘solid-like’ network prevents its leaching from the gel. The LMWG also retains its own unique function – specifically, remediating methylene blue pollutant dye from basic water as a result of non-covalent interactions. The mobile hybrid beads accumulate this dye more effectively than PG-only beads. Self-propelling gel beads have potential applications in removal/delivery of active agents in environmental or biological settings. The ability of self-assembling LMWGs to enhance mobility and control removal/delivery, suggests that adding them into self-propelling systems can add significant value.