title: Reconfigurable Photonic Crystals Enabled by Multistimuli-Responsive Shape Memory Polymers Possessing Room Temperature Shape Processability.
abstract: Traditional shape memory polymers (SMPs) are mostly thermoresponsive, and their applications in nano-optics are hindered by heat-demanding programming and recovery processes. By integrating a polyurethane-based shape memory copolymer with templating nanofabrication, reconfigurable/rewritable macroporous photonic crystals have been demonstrated. This SMP coupled with the unique macroporous structure enables unusual all-room-temperature shape memory cycles. "Cold" programming involving microscopic order-disorder transitions of the templated macropores is achieved by mechanically deforming the macroporous SMP membranes. The rapid recovery of the permanent, highly ordered photonic crystal structure from the temporary, disordered configuration can be triggered by multiple stimuli including a large variety of vapors and solvents, heat, and microwave radiation. Importantly, the striking chromogenic effects associated with these athermal and thermal processes render a sensitive and noninvasive optical methodology for quantitatively characterizing the intriguing nanoscopic shape memory effects. Some critical parameters/mechanisms that could significantly affect the final performance of SMP-based reconfigurable photonic crystals including strain recovery ratio, dynamics and reversibility of shape recovery, as well as capillary condensation of vapors in macropores, which play a crucial role in vapor-triggered recovery, can be evaluated using this new optical technology.
authors.forename: Yin
authors.initials: Y
authors.lastname: Fang
authors.forename: Sin-Yen
authors.initials: SY
authors.lastname: Leo
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Ni
authors.forename: Junyu
authors.initials: J
authors.lastname: Wang
authors.forename: Bingchen
authors.initials: B
authors.lastname: Wang
authors.forename: Long
authors.initials: L
authors.lastname: Yu
authors.forename: Zhe
authors.initials: Z
authors.lastname: Dong
authors.forename: Yuqiong
authors.initials: Y
authors.lastname: Dai
authors.affiliation: ITIA-CNR, Industrial Technologies and Automation Institute, National Council of Research , Via Bassini, 15, 20133 Milano, Italy.
authors.forename: Vito
authors.initials: V
authors.lastname: Basile
authors.forename: Curtis
authors.initials: C
authors.lastname: Taylor
authors.forename: Peng
authors.identifier: http://orcid.org/0000-0001-8446-4096
authors.initials: P
authors.lastname: Jiang
keywords: chromogenic; cold programming; multistimuli-responsive; photonic crystals; shape memory polymers