Enhancing the tactile and near-infrared sensing capabilities of electrospun PVDF nanofibers with the use of gold nanocages

Abstract

Owing to its piezoelectric and pyroelectric properties, poly(vinylidene fluoride) (PVDF) has been extensively explored for applications related to tactile sensing, energy harvesting, and thermal imaging. However, PVDF cannot be directly used to detect light because of its weak absorption in the visible and near-infrared (NIR) regions, preventing effective conversion from light to heat and then electrical signal. In this work, we address this issue by incorporating Au nanocages (AuNCs) into PVDF nanofibers during electrospinning. The strong and tunable optical absorption associated with AuNCs makes them an effective transducer for converting light to heat and then electrical signal. The presence of AuNCs and the strong electric field inherent to electrospinning both promote the formation of the ferroelectric β phase for maximal piezoelectric and pyroelectric conversions. With the incorporation of AuNCs, the electrospun PVDF nanofibers show enhanced capabilities for tactile and NIR sensing. While the voltage output under the tactile force is increased by 12.6-fold relative to the case of pristine PVDF nanofibers, a voltage output of 7.2 V is achieved when the hybrid device is subjected to the on/off cycles of NIR irradiation by an 808-nm diode laser at a power density of 0.2 W/cm2.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

“…With the incorporation of Au nanocages, the electrospun PVDF nanofibers were found to exhibit greatly enhanced capabilities for tactile and near-infrared sensing. 1002 In another report, the nonwoven mat of PVDF nanofibers loaded with Au nanocages was applied to highly effective evaporation of water via photothermal heating. 1003 Because PVDF is highly hydrophobic, its nonwoven mat naturally floats on the surface of water without sinking.…”

Poly(vinyl alcohol) triggers Au nanoparticles formation for near‐infrared radiation‐responsive gels and nanofibers

“…Available information on NIR‐responsive nanofibers is very limited. In a previous study, gold nanocages were dispersed in poly(vinylidene fluoride) (PVDF) at a concentration of 0.01% with respect to PVDF and the translucent nanofibers showed an increase in temperature of more than 40 °C under 808 nm laser . The Au NPs concentration was similar to that in our nanofibers assuming that 100% yield conversion of AuAc 3 into Au NPs was achieved.…”

“…The Au NPs concentration was similar to that in our nanofibers assuming that 100% yield conversion of AuAc 3 into Au NPs was achieved. Differently, in the previous studies, the temperature was recorded using an infrared camera that allowed measuring the temperature increase in the very spot center of the irradiated mat . In our case, the temperature was recorded in the external limit of the irradiated spot to avoid any artifact caused by the metallic parts of the PT100 thermocouple.…”

Gold nanocages for effective photothermal conversion and related applications

“…9 Figure 5B shows the calculated scattering, absorption, and extinction spectra of a nanocage composed of 52% Au and 48% Ag with an outer edge length of 54 nm and a wall thickness of 6 nm. 33 The calculated scattering, absorption, and extinction cross sections at resonance were 1.04 × 10 −14 , 2.65 × 10 −14 , and 3.69 × 10 −14 m 2 , respectively. The relative contributions of scattering and absorption to the total extinction of a AuNC can be tuned by varying its size.…”