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Most stretchable film strain sensors generally present nonlinear electrical responses to applied strain, leading to an inaccurate acquisition of sophisticated signals, difficult signal processing, and zero‐calibration, which hampers practical applications severely. Here, a Janus hetero‐structured microarray film sensor is developed by in‐situ growth of silver nanoparticles on the surface of micro‐patterned elastomer films fabricated via low‐temperature imprinting followed by scraping‐induced particle trapping. Heterogeneous property designs in both modulus and electrical conductivity via introducing polymer microarrays enable modulating the electron transport manner in the conductive layer of elastic Janus films upon stretching, allowing to tune signal linearity effectively. Therefore, such a hetero‐structured film sensor shows good signal linearity (fluctuation of gauge factor [GF] below ±0.02) and relatively high sensitivity (GF > 10) within 55% strain, a detection limit of 0.2% strain, and a response/recovery time of 16.3/46.9 ms, respectively. Correspondingly, it enables monitoring human respiration and body motion with higher resolution compared with the nonlinear one, meanwhile, it is capable of detecting tiny pressure to discriminate braille alphabets via touch identification. Overall, it unveils a simple strategy to fabricate film strain sensors for high‐resolution healthcare and body motion monitoring, as well as electronic skins toward tactile sensing and touch identification. [ABSTRACT FROM AUTHOR]

Stretchable electrodes play a crucial role in wearable electronics for high-efficiency carrier transport in the information communication, yet it is challenging to achieve high electrical conductivity at large strain for stretchable and porous conductive composites. Here, a simple yet efficient strategy is proposed to fabricate highly conductive, porous and stretchable composites via seeding hydrophilic carbon nanotube (CNT) oil-in-water microemulsions in elastomer films prior to growing silver nanoparticles (AgNPs) in situ. It aims at forming a dual heterogeneous structure of CNT microspheres in the elastomeric films containing conductive networks of AgNPs, which allow to guarantee the overall good electrical conductivity. Unlike the rapid propagation of cut-through microcracks in conventional conductive network of AgNPs under strain, the mechanical and electrical dual hetero-structured CNT microspheres in the conductive networks can sustain high electrical conductivity at large strains by blocking and cutting off microcrack propagation. Therefore, the porous composite electrodes show electrical conductivity above 103 S/cm at 200% strain thanks to the efficient dissipation of strain energy by dual hetero-structured CNT microspheres, which is controlled by CNT concentration in the oil-in-water microemulsions. Besides, the as-fabricated porous composites sustain high yet stable electrical conductivity at various kinds of mechanical deformations, such as tension, bending, twisting and a combination of them, allowing for the promising application in stretchable and wearable electrodes. [Display omitted] [ABSTRACT FROM AUTHOR]

A flexible strain sensor is developed via one-step in-situ construction of stiff PVDF nanospheres on the surface of TPU fibers via polymeric phase and morphology control technology. It enables tunable linear sensing to strain thanks to the restricting of quick crack propagation. [Display omitted] • Flexible fiber mat strain sensors of heterogeneous structures are developed. • The heterogeneous structure is consisted of stiff PVDF nanospheres on TPU fibers. • The structure can restrict quick micro-crack propagation throughout fiber surface. • The sensor with high-density nanospheres shows very good linearity. Wearable strain sensors with high sensitivity and linear resistance signal response to strain are urgently demanded for human–machine interface, which can be tuned by introducing uneven surface mechanics distribution onto fiber surfaces via structural heterogeneity for fibrous elastomer fiber mat sensors. Yet it is still of great challenge to build micro- or nano-scale heterogeneous structures on fiber surfaces in a facile and scalable way without using templates. Herein, we report a plastic nanosphere-decorated elastomer fiber mat strain sensor with a zoned surface strain energy release characteristic, designed based on analysis of material match and structural mechanics. Surface mechanics analysis confirms that the as-designed sensor shows a controllable strain energy release area, significantly improving sensing stability thanks to effective restriction of micro-crack propagation in conductive pathways. In particular, fibrous mat sensor with high-density nanospheres shows very low fluctuation in strain sensitivity variation (±0.05 for strain ≤ 30 %), i.e., good linearity in the resistance response to strain, while that for the control sensor is ± 10.0 for strain ≤ 16 %. Such a fiber mat strain sensor can not only be applied for real-time sensing of object deformations for human–machine interface and intelligent control, but also in hydrophobic porous elastomeric packaging materials and triboelectric devices. [ABSTRACT FROM AUTHOR]