Convex micropatterned arrays in fused silica glass surface from the uniaxial thermal imprinting of thermoplastic nanocomposites

The sintering of silica nanoparticles (SiNPs) for fused silica glass structural components has garnered significant interest due to its cost-effective and scalable production, as well as potential applications in optics, resonators, and microfluidics. Fabricating thermoplastic nanocomposites (NCs) by combining SiNPs with an organic polymer binder for thermal imprinting using a hard mold, followed by debinding and sintering, represents a promising approach. However, the mechanisms of high-quality cavity filling and the influence of polymer binders on sintering quality remain poorly understood. Here, an improved uniaxial thermal-imprinting technology was developed, utilizing thermoplastic NCs combined with dimethyl silicone oil and hydrophobic SiNPs as mold lubricants. The effects of polyvinyl butyral (PVB) binder's molecular weight and content on sintering performance were systematically investigated. Optimizing these parameters significantly enhanced fused silica glass convex microstructures, achieving a surface roughness Sa = 48.2 nm, visible light transmittance exceeding 90 %, and an aspect ratio of 0.84. This study provides a practical framework for fabricating micropatterned fused silica glass parts with complex shapes, offering potential applications in optics, resonators, microfluidic chips, and beyond.