###### Abstract  
Controlling morphology of polysiloxane blends crosslinked by the hydrosilylation reaction followed by pyrolysis constitutes a robust strategy to fabricate polymer-derived ceramics (PDCs) for a number of applications, from water purification to hydrogen storage. Herein, we introduce a dissipative particle dynamics (DPD) approach that captures the phase separation in binary and ternary polymer blends undergoing hydrosilylation. Linear polyhydromethylsiloxane (PHMS) chains are chosen as preceramic precursors and linear vinyl-terminated polydimethylsiloxane (\(v\)-PDMS) chains constitute the reactive sacrificial component. Hydroisylation of carbon-carbon unsaturated double bonds results in the formation of carbon-silicon bonds and is widely utilized in the synthesis of organosilicons. We characterize the dynamics of binary PHMS/\(v\)-PDMS blends undergoing hydrosilylation and ternary blends in which a fraction of the reactive sacrificial component (\(v\)-PDMS) is replaced with the non-reactive sacrificial component (methyl-terminated PDMS (\(m\)-PDMS), polyacrylamide, or poly(methyl methacrylate) (PMMA)). Our results clearly demonstrate that the morphology of the sacrificial domains in the nanostructured polymer network formed can be tailored by tunning the composition, chemical nature, and the degree of polymerization of the sacrificial component. We also show that the addition of a non-reactive sacrificial component introduces facile means to control the self-assembly and morphology of these nanostructured materials by varying the fraction, degree of polymerization, or the chemical nature of this component. polymer-derived ceramics; phase separation; dissipative particle dynamics; hydrosilylation reaction +
Footnote †: journal:  
results in the formation of a ladder-type network structure [12; 13]. The hydrosilylation reaction between the silicon-hydrogen group of PHMS and the vinyl groups of an olefin, such as divinylbenzene (DVB) or vinyl-terminated polydimethylsiloxane (\(v\)-PDMS), provides a facile method of crosslinking and is widely used in synthesis of organosilicons [14; 15; 16]. Due to the complete decomposition during pyrolysis, PDMS is often selected as the pore former (or the sacrificial component) to fabricate porous PDCs [9; 17; 18]. The morphology of phase-separated precursors significantly affects the structure of the PDCs. It had been shown that the obtained macroporous ceramics closely resemble the microstructure of the crosslinked precursors [19]. While the total porosity depends on the fraction of the sacrificial components used [1; 2; 6], the pore size and pore connectivity of PDCs can be controlled via regulating the dynamics of the phase separation process. For example, choosing a sacrificial component of higher viscosity [20] or a higher fraction of a sacrificial component [2; 19; 20] results in larger pores. In the system of PHMS crosslinked with \(v\)-PDMS and a crosslinking enhancer, the size of the generated mesopores was shown to increase with an increase in the molecular weight of \(v\)-PDMS [21]. The miscibility between the polymeric components directly affects the phase separation and subsequent microstructure of PDCs [18; 22]. During the hydrosilylation reaction, silicon-hydrogen (Si-H) bond is added across the unsaturated carbon-carbon double bond (C=C) of an olefin, resulting in the formation of the silicon-carbon (Si-C) bond [23]. This reaction takes place in the presence of a catalyst and is often accompanied by various side reactions (such as dehydroprogenative silylation, hydrogenation of olefins, isomerization and oligomerization of olefins) [23]. Extensive efforts were directed towards designing efficient and selective catalysts for this reaction; notably, hydrosilylation is regarded as one of the most important industrial applications of homogeneous catalysis [24]. Platinum-based (Pt-based) catalysts are primarily used in various industrial applications [24] and are shown to significantly reduce the side products.