Chromogenic Photonic Crystals Enabled by Novel Vapor‐Responsive Shape‐Memory Polymers

Abstract

A new type of shape-memory polymer (SMP) is developed by integrating scientific principles drawn from two disparate fields: the fast-growing photonic crystal and SMP technologies. This new SMP enables room-temperature operation for the entire shape-memory cycle and instantaneous shape recovery triggered by exposure to a variety of organic vapors.

Programmable Macroporous Photonic Crystals Enabled by Swelling‐Induced All‐Room‐Temperature Shape Memory Effects

“…[60] The condensed liquid then rapidly diffuses into the polymer network and expands the deformed macroporous layer. In the vapor-triggered recovery process, as demonstrated in our previous work, the solvent molecules in the vapor phase first condense in the interconnecting macropores through capillary condensation.…”

“…This could significantly impede their optical applications in active devices (e.g., optical switches and displays), which typically require fast response speed. [60][61][62] Unfortunately, these hydrophilic copolymers with very low T g (≈−40 °C) and Young's modulus (E < 10 MPa) are highly brittle and susceptible to water, impeding their applicability in durable nanooptics. Room-temperature "cold" programming has been demonstrated for a variety of SMP systems, such as epoxies, polyurethanes, natural rubbers, polylactic acid-polyurethane blends, and copolymers comprising poly(ε-caprolactone) (PCL).…”

Towards the development of solid-state platform optical sensors: aggregation of gold nanoparticles on polyurethane foam

“…The inability of detection in unclear or colored solutions and instability of some AuNPs in aqueous phase limit time of life of such sensors, whereas changeability of AuNP aggregates makes reevaluation of the analysis difficult. These problems could be overcome using solid-phase sensors [16][17][18][19][20][21][22][23][24].…”

pH and redox-operated nanovalve for size-selective cargo delivery on hollow mesoporous silica spheres

“…Compared with normal cells, tumors have a more acidic internal environment, which shows an excellent prospect for developing pH-responsive mechanized MSNs [29]. To design the stimulus responsive materials, responsive groups were usually introduced into materials [30][31][32][33][34]. Several acidic-sensitive linkers have been reported to form pH stimuliresponsive system, such as a reversible boronate ester linker [35], hydrazones bond [36], imines bond [37] and acetal linker [38].…”