Pritzker School of Molecular Engineering
Published May 15, 2026 | Version v1
Journal article Open

Controlling thermoreversibility and hole conductivity in thermoresponsive ionic biogels using phase morphology for neurohaptics

Creators

  • 1. ROR icon Pennsylvania State University
  • 2. ROR icon Massachusetts Institute of Technology
  • 3. ROR icon University of Chicago
  • 4. ROR icon National Sun Yat-sen University
  • 5. ROR icon Westlake University

Description

Integrating thermoreversibility with electrical conductivity in a unified hydrogel platform enables long-term, reusable through-hair neural interfaces. However, achieving both simultaneously remains challenging, as thermoreversibility demands network reorganization while conductivity necessitates network percolation. Here, we engineer phase morphology by controlling the components’ viscoelastic state during mixing. Ionically conductive nucleated morphologies illustrated by liquid-liquid phase separation exhibit rapid thermoreversibility, whereas electrically conductive bicontinuous phases demonstrated by viscoelastic phase separation achieve a marginal gel-sol transition and an ultralow storage modulus of ~1.7 kilopascals while simultaneously achieving a conductivity of 7.5 siemens per centimeter or transconductance of 5.1 millisiemens in an organic electrochemical transistor. Below this threshold, systems resemble nucleated behavior, whereas above it, superior semiconducting properties emerge, but phase transition capability is lost. These materials enable reusable through-hair neural interfaces to maintain low skin contact impedance of 1.6 kohm·cm2 across different hair types for 3 days, facilitating stable event-related desynchronization detection during mechanical and electrical haptic sensation for personalized haptics.

Data availability

All data and code needed to evaluate and reproduce the results in the paper are present in the paper and/or the Supplementary Materials. This study did not generate new materials.

Files

sciadv.aee0777.pdf

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Additional details

Funding

U.S. National Science Foundation
2319139
U.S. National Science Foundation
2319139
U.S. National Science Foundation
2419142
National Institutes of Health
R21EB030140
National Institutes of Health
T32NS115667
Pennsylvania State University
Leighton Riess Graduate Fellowship
Pennsylvania State University
Diefenderfer Graduate Fellowship in Entrepreneurship

UChicago Information

Division(s)
Pritzker School of Molecular Engineering