Responsive photonic crystals (PCs)
with a nanoscale band gap assembled
by colloidal nanospheres have been increasingly utilized in detection
and sensing devices owing to their attractive ability to change color
in response to external conditions. However, most of the reported
works have been dedicated to single-functional PCs, which can only
be used as sensors or detectors in a specific situation. Thus, producing
a multi-functional PC for various industrial applications remains
a challenge. In this work, multi-functional soft PC films (SPCFs)
with a brilliant structural color and a robust structure are fabricated
by using polystyrene@poly(methyl methacrylate-butyl acrylate) [PS@P(MMA-BA)]
nanospheres with size in the range of 200–350 nm as building
blocks. The SPCFs possess both the mechanochromic and solvatochromic
properties owing to the adjustable photonic band gap under stress
and polar solvent conditions. The mechanochromic effect of the SPCF
under stretching results in a blue shift of the structural color due
to the decrease in lattice spacing. In contrast, the solvatochromic
mechanism of the SPCF is that it can be swollen by polar solvents,
resulting in the increase in the lattice spacing of PCs and a red
shift of the structural color. Meanwhile, the SPCF can keep its original
structural color while stretched for 20 cycles or when the organic
solvent is completely evaporated. Therefore, robust multi-functional
SPCFs fabricated by the self-assembly of PS@P(MMA-BA) nanospheres
under gravity sedimentation can respond to stress and organic solvents,
showing great potential for use in sensors and detectors.
Photoinduced self-crosslinking technology is a great facilitator of 3D bioprinting of silk fibroin (SF) by allowing rapid solidification of a deliberately formulated SF-based photocrosslinkable bioink. A SF-based, photocrosslinked hydrogel was...
Fiber-shaped supercapacitors are desirable candidates for flexible and wearable energy storage devices; however, the ultralow capacitance and intricate fabrication process of electrode materials significantly limits their performances. We exploited a steerable method to generate core-shell α-MnO 2 /graphene fibers (MnGFs), where the sheath of α-MnO 2 with porous network structures were grown in situ intertwined on the core of graphene fiber in a microfluidic-spinning strategy. The as-obtained MnGFs exhibited outstanding mechanical flexibility and could be curled over a teflon rod for continuous production. Furthermore, the fiber-shaped supercapacitors (MGSCs) manufactured with MnGFs were successfullu assembled and exhibited good voluminal specific capacitance (136.7 F cm −3 ), prominent cyclic stability (91.6% retention over 10000 cycles), and high energy density (3.9 mWh cm −3 ). This advantageous performance was achieved by MnGFs with porous network structures, leading to the rich ion pseudocapacitance and numerous electron transport channels. The as-prepared MGSCs could be easily adopted to power 5 light-emitting diodes after completel charging. We believe that our microfluidic spinning strategy can provide a new-style structural design method for efficient electrode materials and promote the progress of wearable electronic products.
Patterned photonic crystals (PCs) have great development potential in the textile field because of their unique high-saturation iridescent pattern displays. Herein, PC-produced patterns were printed on the fabric surface via screen printing technology. The nanosphere dispersion has reached the required level of viscosity for printing (2435 mPa s) and possessed obvious shear thinning after adding 2.5 wt% of synthetic thickener with strong thickening ability. The interference of the thickener to the self-assembly of nanospheres was weakened as the synthetic thickener accounted for a small proportion in the printing precursor, so the regularity of the microstructure evolution of the assembled PCs was in quasi-ordered arrangement that is shortrange order/long-range quasi-order. Therefore, the structurally colored PC pattern exhibited a visual "flicker" effect with certain angular dependence. In addition, the polymer-bearing layer pretreated on the fabric surface enabled to improve the structural stability of the PC pattern. Thus, the patterned PCs obtained via screen printing have promising applications in textile coloration industry.
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