This paper reports a feasible method to prepare polymeric nanocomposites with enhanced dielectric, electromechanical and hydrophobic performance by introducing the core-shell AgNWs@SiO 2 filler into polydimethylsiloxane (PDMS). The homogenous core-shell AgNWs@SiO 2 was firstly synthesized through a two-step sol-gel process. The thicknesses of AgNWs and SiO 2 coating layer are approximately 70 nm and 20 nm, respectively. The dielectric constant is improved effectively due to enhanced interfacial polarization, while extremely low dielectric loss and conductivity are achieved by introducing the insulating SiO 2 interlayer to moderate the internal surface area of core-shell nanowires and restrict the electron transfer between Ag nanowires. Typically, the PDMS nanocomposites with 20 wt% AgNWs@SiO 2 have a dielectric constant of 6.7, nearly 2.7 times larger than that of pure PDMS, and remains a quite low loss of 0.02 at 1 kHz. Meanwhile, nanocomposites also show improved electromechanical and hydrophoic properties. Nanocomposites with 10 wt% AgNWs@SiO 2 exhibit the highest electromechanical sensitivity ( β= 9.04), about 12.6 times higher than that of pure PDMS at 1 kHz. The static contact angle of nanocomposties with 20 wt% AgNWs@SiO 2 reaches 129°. All the improved performances show great potential application for dielectric elastomer material and electrowetting devices.
Jianjun Ding,Niansong Liu,Ganglin Wang,Naiyu Guo,Chao Sun
In response to the shortcomings of traditional surface-enhanced Raman spectroscopy (SERS) substrates, such as short shelf life, poor uniformity, and low selectivity, this study innovatively proposed a three-dimensional composite substrate of CNTs/Ag/AgNWs/SiO 2 . This substrate demonstrates excellent SERS enhancement effects, with a detection limit of 10 −12 mol/L for the probe molecule Rhodamine 6G (R6G) and an enhancement factor (EF) of 8.947 × 10 8 . Further experiments confirmed the substrate’s superior uniformity and stability. The enhancement mechanism was investigated using both experimental methods and the Finite Difference Time Domain (FDTD) approach. When commonly used pesticide thiram was used as the target analyte, the detection limit of the substrate reached 0.1 mg/L, which is significantly lower than the pesticide residue standards of China and the European Union. Additionally, the genetic algorithm (GA)-optimized Back Propagation (BP) neural network was introduced for the quantitative analysis of thiram concentrations. The experimental results indicated that the GA-BP algorithm achieved the training prediction accuracy of 92.5% for thiram, demonstrating good network performance. This method shows good selectivity and has broad application prospects in the detection of toxic chemicals, environmental pollutants, and food additives.
Currently, silver nanowires (AgNWs) are among the most widely studied materials for flexible transparent electronics. Nevertheless, their practical implementation is hindered by inherent limitations in environmental stability and mechanical robustness. To address these challenges, this study presents a straightforward fabrication approach for a multifunctional flexible transparent conductive film (TCF) that exhibits superior mechanical integrity and long-term stability. Through simple solution processing, multiple functional layers were constructed on a flexible substrate. Among them, AgNWs serve as the conductive layer, SiO 2 NPs as the anti-reflection layer, and AZO as the protective layer. Accordingly, an AgNWs/SiO 2 /AZO TCF (ASZ) was fabricated, exhibiting a sheet resistance of 2.85 Ω/sq, a transmittance of 80.8% at 550 nm, and a figure of merit (FoM) value of 588. This TCF not only combines Joule heating and electromagnetic shielding but can also be used to fabricate OLED devices. A transparent Joule heating device fabricated from this TCF achieves a rapid thermal response, reaching 130 °C at 3 V while maintaining stable operation over extended durations. Furthermore, the film delivers an electromagnetic interference (EMI) shielding effectiveness of 32 dB across the X-band (8.2–12.4 GHz). Critically, owing to the outstanding oxidation resistance and superior surface planarity of the AZO layer, the film’s sheet resistance increases by only 24% after a rigorous 70-day aging test under ambient conditions. When employed as the anode in OLED devices, the TCF enables a maximum luminance of 17,400 cd/m 2 . Collectively, this work establishes a scalable, simple, and highly stable strategy for developing multifunctional transparent electronic devices. Download: Download high-res image (324KB) Download: Download full-size image
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