Ultrahigh Stretchability of Organogel Networks: Fiber Evolution and the "Fishing Net Model"

Stretchable gels have attracted tremendous attention in the fields of flexible electronics and wearable devices. However, the lack of systematic observations on microstructural evolution during ultrahigh stretching (above 400%) restricts the rational design of high-performance stretchable gel materials. In this work, a methyl methacrylate (MMA)-based organogel with 0.5 wt % POSS-G1-BOC (POSS = polyhedral oligomeric silsesquioxane, a POSS core organic-inorganic hybrid dendrimer) as the gelator (denoted as MMA/0.5 wt % POSS-G1-BOC) was fabricated. Assisted by 3 M VHB tape, the organogel achieves an unprecedented uniaxial tensile deformation up to 800%. Combining scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and dynamic mechanical analysis (DMA), six regular evolutionary behaviors of the fiber network during stretching from 0% to 900% are systematically revealed: (1) a progressive decrease in fiber diameter; (2) a gradual reduction in mother-fiber spacing; (3) enhanced uniaxial orientation along the stretching direction; (4) an increase in the number of mother-fibers accompanied by shortened and reduced daughter-fibers; (5) the fusion of mother/daughter-fibers with regular-shaped defects at 900% stretching; and (6) stretch-induced growth of POSS-G1-BOC crystalline dots. To elucidate the uniform energy dissipation during ultrahigh stretching, a "Fishing Net model" is proposed, in which the dynamic breakage and recombination of hydrogen bonds between POSS-G1-BOC molecules act as the core driving force. Furthermore, by comparing with the liquid crystal (5CB, 4-cyano-4'-biphenyl)-based gel system, the regulatory role of solvent polarity in fiber formation and tensile performance is clarified. This work provides direct experimental evidence and a theoretical framework for understanding the microstructural changes of gels under ultrahigh stretching and thus guides the development of next-generation stretchable materials.