中国民航飞行学院《Surf. Interfaces》：液态金属/石墨烯-PVA海绵压阻传感器，偏压调控灵敏度

成果简介

柔性压阻传感器凭借其结构简单、功耗低、可直接电读出的优势，在可穿戴健康监测与人体运动捕捉领域展现出巨大潜力。然而，传统器件的灵敏度由制造后固定的导电网络决定，往往难以在器件成型后再行调节，限制了其在多变压力场景下的适应性。因此，开发可在制备后按需调控灵敏度的柔性压阻传感策略具有重要意义。基于此，本文，中国民用航空飞行学院Wenfeng Qin等在在《Surfaces and Interfaces》发表名为”Liquid-metal-reduced graphene oxide/PVA sponge piezoresistive sensor with bias-regulated sensitivity enabled by mechanical sintering”的论文，研究提出了一种基于液态金属/还原氧化石墨烯杂化颗粒（LM@RGO）的偏压调控灵敏度策略。该传感器在酸性介质中使氧化石墨烯（GO）静电组装到带正电的液态金属（LM）液滴表面并原位还原，形成 LM@RGO 颗粒，再将其沉积于多孔 PVA 海绵、经机械烧结构筑连续导电涂层。

此外，LM@RGO 界面将液态金属的高导电性与可变形液态界面，同还原氧化石墨烯（RGO）的界面调控能力相结合，在机械压缩过程中动态调节导电路径的演变，从而优化了压阻响应与偏压依赖的输运行为。经测试，该传感器响应/恢复时间达 60/48 ms，并在超过 6000 次加载-卸载循环中保持稳定；尤为突出的是，将施加偏压由 0.5 V 提升至 3.0 V，最大灵敏度增强 145%（由 0.011 增至 0.027 kPa⁻¹），实现了无需改动结构的灵敏度后调控。同时，该器件还展现出可穿戴运动监测与 4×4 传感器阵列空间压力映射能力，使其适用于柔性人机交互与生理信号采集。本研究提出了一种以机械烧结构筑 LM@RGO/PVA 海绵导电网络、并以偏压调控灵敏度的策略，该策略显著增强了柔性压阻传感器的适应性与可调性，并为制造后可编程调控的 wearable 传感器件提供了新的思路。

图文导读

Fig. 1. Schematic illustration of the preparation process of the LM@RGO/PVA sponge.

Fig. 2. (a) Schematic illustration of the conductive network evolution during the mechanical sintering process. (b) Assembly structure of the LM@RGO/PVA sponge-based piezoresistive pressure sensor.

Fig. 3. SEM images of the LM@RGO conductive coating. (a–c) LM droplets surface-modified with GO/RGO at GO mass fractions of 0.1, 0.3, and 0.5 wt% relative to LM, respectively. (d) Low-magnification image of the LM@RGO particles. (e, f) Coated samples before and after mechanical sintering. (g) High-magnification SEM image of the pristine PVA sponge surface. (h, i) Fracture-section SEM images before and after mechanical sintering.

Fig. 4. (a) Zeta potentials of the LM dispersion, GO dispersion, and LM@RGO dispersion. (b) Raman spectra of GO and LM@RGO. (c) XPS survey spectrum of LM@RGO. (d) C 1 s XPS spectrum of the GO aqueous dispersion. (e) Self-assembly and reduction of GO on LM droplets under acidic conditions. (f) C 1 s XPS spectrum of the LM@RGO particles after reaction in the acidic LM-containing solution. (g) Particle size distribution of LM@RGO. (h) Tensile fracture curves of the original PVA sponge and the LM@RGO-coated sponge. (i) Cyclic compressive stress–strain curves of the LM@RGO/PVA sponge under repeated loading–unloading cycles.

Fig. 5. (a) Relative current change (ΔI/I₀) as a function of pressure at a bias voltage of 2.0 V, together with linear fitting in different pressure regions. (b) Response and recovery times of the sensor. (c) Response signals under different loading rates. (d–f) Cyclic response signals under different applied pressures over five loading-unloading cycles. (g) Stepwise electrical response under gradient pressures. (h) Electrical response of the sensor under micro-pressure stimuli. (i) Photograph of the pressure-sensing test setup. (j) Long-term cycling stability of the sensor over 6000 loading-unloading cycles.

Fig. 6. (a) Electrical testing configuration and simplified equivalent circuit model. (b) Pressure-induced increase in effective contact area and conductive pathways under compression. (c) Bias-assisted charge transport under the same pressure stimulus. (d) I–V curves under different pressures in the range of 0–1 V. (e) log I − log V plot at 0 kPa.

Fig. 7. (a) Photograph of the fabricated sensor. (b) Finger bending. (c) Elbow motion. (d) Continuous finger tapping. (e) Wrist motion. (f) Knee bending. (g) Response under weight loading.

小结

总而言之，本研究以机械烧结的 LM@RGO/PVA 海绵为平台，开发了一种具有偏压调节灵敏度的柔性压阻传感器。GO 在酸性介质中组装到带正电的液态金属液滴表面并在其表面还原形成 LM@RGO 颗粒；机械烧结将初始分离的颗粒转化为更连续的导电涂层，并改善了其在多孔 PVA 框架上的保留率。研究结果表明，所制传感器响应/恢复时间为 60/48 ms，在超过 6000 次加载-卸载循环中保持稳定；将偏压由 0.5 V 提升至 3.0 V 可使最大灵敏度增强 145%（0.011→0.027 kPa⁻¹），实现了制造后的灵敏度按需调控。同时，电气分析表明该行为源于压缩增强的导电接触与偏压敏感的 LM@RGO 网络界面传输的协同作用。因此，本研究有望为可在制备后编程调控的柔性压阻传感器提供新的见解。此外，可穿戴运动监测与 4×4 阵列空间压力映射的应用演示，进一步拓展了该器件在人机交互与生理信号采集中的前景。

文献：https://doi.org/10.1016/j.surfin.2026.110510