Precise Network Polymerized Ionic Liquids for Low-Voltage, Dopant-Free Soft Actuators

Next-generation material applications require electroactive materials for actuation which are light weight, operate at low voltages (<5 V), exhibit cyclability, and are compatible with a range of environments. Here, a class of network polymerized ionic liquid (n-PIL) actuators is reported, synthesized via a facile step growth polymerization, which not only have comparable actuation strains (≈0.9%) to other state-of-the-art ionic polymer systems at ±3 V, but also exhibit 85% performance preservation after 1000 testing cycles and operate with no additives such as solvent or free ionic liquid. Molecular engineering of the n-PILs by controlling crosslinking density and linker polarity leads to an order-of-magnitude increase in tip displacement which provides insights on future materials development.