Construction of effective conductive network of the core-shell SiO2 microspheres hybrid MWCNTs in NR matrix

Abstract

Carbon nanotube (CNT)-filled conductive elastomer composites are considered prime materials for future applications in flexible sensors, electromagnetic shielding, and other related fields. However, the production of CNT-based conductive composites that are low-cost, uniformly dispersed, and exhibit excellent conductivity remains a key challenge for researchers. In this study, we conducted research focusing on both the preparation process of SiO₂@Ag/MWCNTs hybrid fillers and the industrial feasibility of the fillers. Building on the volume exclusion effect of m-SiO₂ and the interfacial enhancement of Tannic acid (TA), we employed dopamine as a surface activator combined with electroless silver plating to metallize the surface of m-SiO₂. The silver-coated m-SiO₂ microspheres and MWCNTs were processed via ultrasonic treatment to form SiO₂@Ag/MWCNTs hybrid fillers (ISSMH). Effects of varying dopamine deposition time and silver plating time on the core-shell structure of the microspheres is investigated. Additionally, natural rubber was used as the matrix to study NR/ISSMH nanocomposites using a controlled variable method. After evaluating different silver plating processes, we developed an eco-friendly, efficient silver plating technique that increased the volume conductivity of the NR/ISSMH nanocomposites to 1.8 × 10⁻² S cm⁻¹, representing a two-order-of-magnitude improvement over the uncoated nanocomposites. Moreover, composites with different filler loadings demonstrated superior thermal conductivity compared to previous work on nanocomposites. This study not only provides a novel approach to addressing the dispersion challenges of conductive fillers but also has promising implications for applications in flexible sensors, electromagnetic shielding, and human motion detection.