Hydrophobic CNF/MXene composite aerogels with synergistic structure–interface engineering for reliable flexible sensing

Abstract

Flexible piezoresistive aerogels are promising for wearable electronics and sensing in complex environments, yet their practical application is often limited by structural collapse during compression and moisture-induced conductive instability. Herein, an ultralight hydrophobic CNF/MXene composite aerogel is developed through synergistic structure–interface engineering. Directional freeze-casting creates vertically aligned lamellar channels that effectively confine compressive deformation and guide the assembly of MXene into continuous conductive pathways. Meanwhile, in situ vapor-phase deposition of methyltrichlorosilane (MTS) establishes a stable hydrophobic interface that suppresses moisture-induced softening and conductive fluctuations. Benefiting from the synergy between ordered structural regulation and interfacial stabilization, the resulting aerogel exhibits an ultralow density of 1.7 mg cm⁻³, a water contact angle of 146.1°, and a high sensitivity of 438.65 kPa⁻¹ over 0-98 kPa, together with stable operation over 1000 compression cycles. Reliable sensing performance is maintained under coupled high-temperature, high-humidity, and dynamic compression conditions. In addition, the aerogel demonstrates rapid photothermal conversion capability, reaching 179.6°C under light irradiation. This work provides a practical strategy for constructing environmentally reliable porous conductive aerogels and offers new insights into the cooperative regulation of deformation behavior and interfacial stability for flexible sensing applications.