Polysiloxane Derived Macroporous Silicon Oxycarbide Microspheroidal Particles and Their Decoration with 1D Structures

Abstract

A simple method of synthesis for the macroporous SiOC spheroidal microparticles was developed. Preceramic polysiloxane macroporous microbeads were obtained by a one-step aqueous emulsion process involving poly(hydromethylsiloxane) (PHMS) with the addition of FeCl 3 ·6H 2 O. Thermal treatment of these particles gave various SiOC materials depending on the pyrolysis temperature. Hierarchically porous spheroidal mezo-macroporous ceramers were obtained at 600 °C. Heating at 850-1000 °C gave SiOC ceramic spheroidal particles with about 60% open porosity. Ceramization at 1200-1400 °C led to the particles decorated with ceramic whiskers and wires. Heating at 1600 °C gave wires and spilled ceramic particles. These 1D ceramic structures were formed by a Vapor-Liquid-Solid (VLS) mechanism.

Single-source-precursor derived SiOC ceramics with in-situ formed CNTs and core–shell structured CoSi@C nanoparticles towards excellent electromagnetic wave absorption properties

“…The VLS growth is mostly due to the catalytic reaction growth mechanism, and liquid metal-based particles are therefore used as active catalysts for gas-phase reactants. Characteristic features of the VLS mechanism is related to the formation of metal-containing tips at the end of 1D structured nanowires, nanofibers, and nanotubes [41][42][43]. In the present work, it is assumed that the VLS mechanism controls the in-situ growth of CNTs because the round spherical particles or the droplets at the top of the nanotubes were observed by means of the SEM.…”

“…In general, growth modes of 1D nanostructures are mainly classified into vapor-liquid-solid (VLS) and vapor-solid (VS) growth mechanisms [40][41][42]. The VLS growth is mostly due to the catalytic reaction growth mechanism, and liquid metal-based particles are therefore used as active catalysts for gas-phase reactants.…”

Micron-Sized Thiol-Functional Polysilsesquioxane Microspheres with Open and Interconnected Macropores: Preparation, Characterization and Formation Mechanism

“…They have been applied in the fields of drug delivery [ 7 ], catalyst support [ 8 ], energy storage [ 9 ], adsorption [ 10 ], separation [ 11 , 12 ], etc. Among different types of pores, macropores have the advantage of easy and rapid mass transfer along pore channels, which can promote the interaction between the exterior substances and the active sites in materials [ 13 , 14 ]. However, introducing pore structures, especially macropores, into some functional materials is still a challenge.…”