Minimal contact formation between hollow glass microparticles toward low-density and thermally insulating composite materials

In this study, syntactic foams composed of maximal hollow glass microparticles (HGMPs) volume fraction with improved thermal insulation performance and reasonable mechanical strength were fabricated through a new manufacturing approach. Use of low fraction binder materials diluted in solvent enabled minimal contacts among the HGMPs assisted by a natural capillary trend, as confirmed by in situ and ex situ optical and electron microscope imaging. Composite level samples of practical thickness, fabricated by a layer-by-layer coating approach, exhibited enhanced thermal insulation performance, as characterized by infrared thermal imaging and quantitative thermal conductivity measurement. Via microscope inspection under tensile loading, a favorable particles-binder bonding trend was inspected in terms of mechanical strength. The fabricated composite materials have potential for building insulation applications because of their relatively simple and scalable manufacturing nature, minimal use of binder materials, and mechanical strength to maintain and tailor shape. Further studies are necessary to understand mechanical and thermal properties of the composites, and key fabrication mechanisms involved with self-assembly under complex multi-components and phases.