α‐Methyl‐Induced Hydrophobic Shielding and Polymer Microphase Separation Stabilize Interpolymer Complexation in Tough Eutectogels

ABSTRACT

Developing mechanically robust eutectogels with stable ionic conductivity in highly polar deep eutectic solvents (DESs) remains challenging due to strong solvation effects that weaken interpolymer interactions. Here, a P(MAA‐ co ‐NIPA)/Choline chloride–ethylene glycol (ChCl–EG) copolymer eutectogel is developed via one‐step photopolymerization, in which microphase separation and localized hydrophobic shielding synergistically stabilize interpolymer hydrogen bonding. The limited solubility of poly(N‐isopropylacrylamide) (PNIPA) in the DES induces phase separation, forming polymer‐rich domains that enrich carboxyl and amide groups and promote interchain hydrogen bonding. Meanwhile, the α‐methyl groups along the PMAA backbone create localized hydrophobic microenvironments that reduce solvent accessibility and suppress solvation screening, thereby stabilizing interpolymer complexation. This combined mechanism enables a balance between mechanical reinforcement and energy dissipation. As a result, the eutectogel exhibits high tensile strength (0.91 MPa), high toughness (3.11 MJ m ⁻³ ), and large extensibility (721%), along with high optical transparency (∼90%). It also demonstrates tunable ionic conductivity (1.29 mS cm ⁻¹ at room temperature), wide temperature tolerance, self‐healing ability, and reliable strain‐sensing performance. This work provides a molecular‐level design strategy for stabilizing noncovalent interactions in highly polar media and offers insights into the development of robust and multifunctional soft ionic conductors.