Solvent-free and one-step fast fabrication of a side-chain liquid crystalline network

초록

Liquid crystal networks (LCNs) are advanced materials with applications in medical devices and aerospace owing to their reversible adhesion, shape memory, and self-healing properties. Traditional LCN synthesis involves acrylate-based liquid crystal (LC) monomers and photopolymerization; however, it has limitations such as oxygen sensitivity, shrinkage, and thickness constraints. Epoxy-based LCNs using anionic ring-opening polymerization overcome some of these issues but still face challenges such as the need for high-purity solvents and reduced thermal and mechanical properties due to short-chain polymers. Here, we present a solvent-free, onestep, fast-curing method for synthesizing LCNs via heat compression in an atmospheric environment. This process incorporates LC diepoxide (D), acting as a chain extender and crosslinker, with LC monoepoxide (M), forming the side-chain linear polymer. Imidazole initiates the curing reaction at LC temperatures, ensuring fast curing and optimized crystallinity, which successfully induces LCN formation. Increasing the D content improves chain extension or crosslinking, forming LCN networks with varying crosslinking densities. All samples exhibit thermal conductivity over 0.55 Wm- 1K- 1. Samples with a higher D content demonstrate superior mechanical properties and thermal stability. Notably, samples with a balanced epoxide ratio exhibit crystalline structures and the highest thermal conductivity. This method efficiently enables the cost-effective production of epoxy-based LCNs with customizable properties.

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