Photonic cognition of liquid crystal polymers for unlocking electrical locomotion

The artificial replication of learning phenomena is an emerging domain with proven social impact. In this paper, we advance composite responsive material behavior toward learning by inducing memory-dependent functions through repeated exposure to a priming stimulus. For this, we integrate a photochromic spiropyran dopant into our liquid crystal network (LCN) to control its electrical actuation. UV light irradiation increases charge density by triggering the spiropyran-to-merocyanine zwitterion conversion, “gating” the permittivity of the LCN, and reducing the alternating electric field strength threshold required for actuation by up to 67.8% from its initial state. This UV-gating effect persists in the LCN as a memorized behavior. Resembling biological memory, the UV-gated memory is reversible and erased from the material over time. This is accelerated by up to 20% by irradiation with a green light “memory-wiping” agent. We envision that our work will contribute to the development of artificially intelligent materials for self-learning appliances and medical devices.