AC-field-assisted Te nanowire-PDMS composites with concentration-dependent electromechanical output enhancement under bending deformation

초록

We present a scalable route to fabricate flexible Te nanowire (Te NW)-PDMS composites with enhanced bending-induced electromechanical output by using an AC electric field to induce field-guided in-plane assembly of the nanowires. Single-crystalline Te NWs synthesized via a solution-phase reduction process were dispersed in PDMS at loadings of 0.05-3 wt% and aligned between planar electrodes under an AC field (450 V, 50 Hz). The optimized 0.5 wt% aligned composite produced a peak output voltage of 13.9 V, representing a 2.4-fold enhancement compared with a randomly dispersed counterpart, which is consistent with improved stress transfer and microstructure-dependent electromechanical signal amplification in the soft composite. Optical microscopy and cross-sectional SEM confirmed the formation of field-guided chain-like nanowire assemblies, while XRD and TEM verified the trigonal Te phase and high crystallinity. At higher NW contents (>= 0.7 wt%), aggregation and dense bundles reduced the effective deformation of individual NWs and degraded the output signal. Additional measurements performed under a different bending condition further supported the concentration-dependent enhancement trend, and a pure PDMS control device generated only similar to 240 mV under identical testing conditions, indicating that the dominant output enhancement originates from the Te nanowire network rather than the polymer matrix alone. This field-assisted assembly strategy provides a simple and versatile platform for enhancing electromechanical output in soft nanowire/polymer composites and offers useful design insight for future flexible sensing and motion-monitoring systems.

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