Programmable Photothermal Actuation using Novel Negative Photochromic Donor-Acceptor Stenhouse Adduct (DASA) Polymers*

Light-driven actuation has significant advantages including untethered operation, precise spatiotemporal activation, and the ability to operate in complex surroundings without significant modification. Here, we use a new class of molecular photoswitches, called donor-acceptor Stenhouse adducts (DASAs), to generate a novel but conceptually simple photo-responsive polymer bilayer actuator, capable of repeatedly lifting a load against the force of gravity. We will present a synthesis pathway for chemically attaching DASA conjugates to poly(hexyl methacrylate) through norbornadiene click chemistry, and will demonstrate actuator performance. Importantly, we can leverage the different time scales of photothermal and photochemical responses of DASAs to achieve dynamic material control, including the ability to switch on and off actuation. Our results highlight the promising benefits of high molar absorptivity, negative photochromism, and visible light absorption of DASAs for actuation.