Polycarboxylate superplasticizer-mediated hierarchical interfacial engineering enables advanced dual-mode strain–temperature sensing in thermoplastic polyurethane/ionic liquid ionogels

Abstract

Ionic liquid (IL)-based flexible sensors show great promise for wearable electronics, yet their practical application is significantly hindered by poor interfacial compatibility between the IL phase and the polymeric matrix, leading to issues such as ion leakage and phase separation. To address this challenge, we introduce a novel hierarchical interfacial engineering strategy mediated by a polycarboxylate superplasticizer (PCE) to fabricate advanced dual-mode strain–temperature sensing thermoplastic polyurethane (TPU)/IL ionogels. The as-prepared TPU/IL/PCE ionogel demonstrates exceptional sensing performance, including an ultra-wide strain-sensing range (0–1000%), a low detection limit (0.05% strain), outstanding durability (4000 cycles at 20% strain), and reliable temperature sensing capabilities (0.1 °C resolution and −2% °C⁻¹ sensitivity). The superior performance can be attributed to the unique hierarchical interfacial design facilitated by PCE. At the molecular level, PCE anchors IL molecules through electrostatic forces, effectively suppressing ion mobility and preventing ion leakage. Simultaneously, the comb-like architecture of PCE physically entangles with TPU chains, reinforcing the network structure and inhibiting chain slippage under deformation. These synergistic effects ensure mesoscopic homogeneity and macroscopic stability, enabling the ionogel to maintain uniform IL dispersion and structural integrity even under extreme deformation conditions (up to 1000% strain). This work presents a straightforward yet powerful interfacial engineering approach that significantly enhances the long-term reliability and sensing performance of flexible ionogels, paving the way for their practical deployment in next-generation wearable electronics, electronic skins, and soft robotics.