The research team led by Prof. Xinglong Gong at the University of Science and Technology of China has developed a high-strength and tough PVA ionic gel through a synergistic enhancement strategy. By combining in situ localised alignment with salting-out treatment, the gel exhibits tunable strength and toughness, demonstrating remarkable protective performance and energy dissipation in both puncture resistance and high-speed ballistic impact tests.
Fig. 1. Schematic illustration of the preparation process of PL-gel.
A synergistic strategy: in situ localised alignment with salting-out
- The fabrication begins with dissolving PVA in ethylene glycol, freezing to form an organogel, and then fixing the gel at both ends during ionic liquid exchange. The fixation restricts shrinkage, creating tensile stress that gradually aligns polymer chains. Simultaneously, the ionic liquid promotes salting-out, driving further aggregation and crystallisation of PVA chains.
- The result gel is a highly entangled and micro-oriented structure, in which robust ionic and hydrogen-bonding networks stabilize the gel. Compared to conventional salt solutions, ionic liquids provide higher ion-exchange capacity and thermal stability, forming a more reliable polymer network.
The PL-gel demonstrates exceptional mechanical properties:
- Tunable tensile strength: 18.1–62.2 MPa
- Toughness: 56.8–123.7 MJ m⁻³
- Young’s modulus: 18.8–187.8 MPa
Broad applicability
Importantly, this toughening strategy is not limited to PVA-based gels. We demonstrated its generality by applying it to PAAM hydrogels, which also exhibited improved mechanical and protective performance. This highlights the potential of the approach as a universal route to design high-performance polymeric gels.
Towards next-generation protective and flexible materials
This study shows that by carefully controlling chain alignment and molecular interactions, it is possible to engineer ionic gels that combine strength, toughness, and resilience. The PL-gel is transparent, highly tough, and capable of withstanding both puncture and ballistic impact, opening new opportunities for advanced flexible electronics, protective gear, and aerospace applications.
Link: https://doi.org/10.1038/s41467-025-63148-0