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A high voltage fiber spinning technique that freezes two polymers into a tangled network keeps zwitterionic hydrogels — water swollen, charge balanced gels — stretchy and antifouling at once.
Soft electronic devices that the body fouls, scars over, or tears apart within weeks have forced a stubborn compromise on materials chemists. The gels that best resist fouling are too weak to survive, and the gels that are tough enough tend to trigger that fouling in the first place. A paper in Advanced Materials reports a way out of that bind.
The team works with zwitterionic hydrogels: water-swollen polymer networks whose positive and negative charges help them shrug off proteins, cells, and bacteria. They used electrospinning, a technique that pulls a polymer solution into ultrafine fibers with a high-voltage field, to co-dissolve a hydrophilic zwitterionic polymer with a hydrophobic one. Solvent evaporation happens in milliseconds, fast enough to kinetically trap the two polymers in a tangled state before thermodynamics can pull them apart. The result is a composite that preserves the antifouling (fouling-resistant) behavior of the zwitterionic phase while gaining mechanical strength.
The reported numbers: tensile strength of 2.48 MPa, stretchability past 1040%, and fracture toughness (the energy a material absorbs before tearing) of 27.76 kJ m⁻², a claimed three-order-of-magnitude jump over pure zwitterionic gels. The team also showed the material recording clean electromyography (EMG) signals and stimulating the sciatic nerve in living rats over two weeks.
A separate Nature Communications paper takes a different route, using consolidated supramolecular networks (Nature Communications 2025). The two strategies have not yet been tested against each other.