Highly Processable Ionogels with Mechanical Robustness

Abstract

Currently, the increasing needs of conductive ionogels with intricate shapes and high processability by individual requirements of next-generation flexible electronics constitute significant challenges. Here, the design of highly processable ionogels is reported with mechanical robustness by self-assembly of a common triblock copolymer into a precursor in functional mixed ionic liquids (ILs) containing conductivity-enhancing and polymerizable strength-enhancing components. The subsequent in situ polymerization of the precursor forms physical-co-chemical cross-linked networks, in which the entanglement between physical and chemical cross-linked networks and microphase separation give rise to mechanical robustness of as-fabricated ionogel. The viscosity of the self-assembled precursor can be rationally tuned, which makes the fabrication process compatible with diverse technologies including inkjet printing, spray coating, and 3D printing. By virtue of highly processable capability of the designed ionogels, an auxetic-structured ionogel can be easily generated using 3D printing, which exhibits greatly improved sensitivity and thus is able to monitor tiny deformations. This study that relies on designing functional mixed ILs as the dispersion phase rather than focusing on synthesizing newtype polymers establishes a new route for versatile and programmable fabrication of high-performance ionogels for broader applications.

Simultaneously enhancing the mechanical robustness and conductivity of ionogels by in situ formation of coordination complexes as physical crosslinks

“…Our tough ionogels are positioned in the rightmost area of the plot, indicating that they possess superior fracture strength compared to the best-in-class conductive ionogel while maintaining competitive ionic conductivity. 26,[30][31][32][33][34][35][36][37] This highlights the unique design and excellent properties of our ionogels.…”

Superstrong Ionogel Enabled by Coacervation-Induced Nanofibril Assembly for Sustainable Moisture Energy Harvesting

“…15,16 Therefore, improving the mechanical properties of ionogels can greatly expand their application scope. 17 Although diverse approaches have been reported to strengthen mechanical properties of ionogels, including microphase-separated ionogel, 16 halometallate IL ionogel, 17 microsphere-entangled ionogel, 18 and double-network or physical-co-chemical cross-linked network ionogel, 19 the strength and modulus of ionogels are still limited due to the plasticization effect of ILs. 20 In addition, the dense homogeneous block formed by the polymer matrix increases the mass transfer resistance of the ionogels, which leads to relatively low ionic percolation and selectivity.…”

“…Nevertheless, current ionogels exhibit poor mechanical properties, such as inferior strength (<1 MPa), toughness (∼1000 J m –3 ), and Young’s modulus (<0.1 MPa), so most ionogels are applied in areas like flexible sensors but fail in applications where superhigh strength is required, such as batteries and energy harvesting devices. , Therefore, improving the mechanical properties of ionogels can greatly expand their application scope . Although diverse approaches have been reported to strengthen mechanical properties of ionogels, including microphase-separated ionogel, halometallate IL ionogel, microsphere-entangled ionogel, and double-network or physical- co -chemical cross-linked network ionogel, the strength and modulus of ionogels are still limited due to the plasticization effect of ILs . In addition, the dense homogeneous block formed by the polymer matrix increases the mass transfer resistance of the ionogels, which leads to relatively low ionic percolation and selectivity .…”

Fluorine-Containing Ionogels with Stretchable, Solvent-Resistant, Wide Temperature Tolerance, and Transparent Properties for Ionic Conductors

“…Ideas for the preparation of ionogels are often borrowed from the preparation of hydrogels. For network construction, design ideas usually include dual network structures [18][19][20], interpenetrating networks [21][22][23], copolymer single-layer network structures [24][25][26], etc. The materials that make up the ionogel network are largely based on polyelectrolytes and hydrophilic polymers, such as polyvinyl alcohol [17,27,28], polyacrylic acid [29,30], and polyacrylamide [31,32].…”