Efficient and large scale printing of photonic crystal patterns with multicolor, multigrayscale, and fine resolution is highly desired due to its application in smart prints, sensors, and photonic ...devices. Here, an electric‐field‐assisted multicolor printing is reported based on electrically responsive and photocurable colloidal photonic crystal, which is prepared by supersaturation‐induced self‐assembly of SiO2 particles in the mixture of propylene carbonate (PC) and trimethylolpropane ethoxylate triacrylate (ETPTA). This colloidal crystal suspension, named as E‐ink, has tunable structural color, controllable grayscale, and instantly fixable characteristics at the same time because the SiO2/ETPTA‐PC photonic crystal has metastable and reversible assembly as well as polymerizable features. Lithographical printing with photomask and maskless pixel printing techniques are developed respectively to efficiently prepare multicolor and high‐resolution photonic patterns using a single‐component E‐ink.
Electric‐field‐responsive and photocurable liquid photonic crystals composed of SiO2 particles, propylene carbonate, and trimethylolpropane ethoxylate triacrylate are used as E‐ink to prepare multicolor and high‐resolution photonic crystal patterns by lithographic and pixel printing methods, respectively.
Abstract
Electrically responsive photonic crystals are promising materials for electrophoretic color displays with better brightness and color saturation. However, electric field must always be ...applied to maintain the specific colors, which brings concerns about the power consumption and signal stability and reversibility. Here, we show an electrically responsive photonic crystal with two stable states at 0 V, which are the colored state or the colorless state with ordered or disordered particle arrangement. The color state can be reversibly switched by applying a short-time electrical field, just like in the case of commercial electrophoretic ink. With optimized recipe and electric field, the photonic crystals encapsulated in the prototype display panel are proved to have potentials in high resolution, multi-color, and greyscale display, which lays down a firm basis for reflective displays with low power consumption and good visibility.
Traditional photonic sensing based on the change of balanced reflection of photonic structures can hardly distinguish chemical species with similar refractive indices. Here a sensing method based on ...the dynamic reflection spectra (DRS) of photonic crystal gel has been developed to distinguish even homologues, isomers and solvents with similar structures and physical properties. There are inherent relationships between solvent properties, diffusion behaviour and evolution of reflection signals, so that the geometric characteristics of DRS pattern including ascending/descending, colour changes, splitting/merging and curvature of reflection band can be utilized to recognize different organic solvents. With adequate solvents being tested, a database of DRS patterns can be established, which provide a standard to identify an unknown solvent.
The aim of this study is to construct and validate “physical literacy self-assessment questionnaire” (PLAQ) for Chinese students in grades 3–6. This study uses qualitative and quantitative methods to ...construct evaluation indicators of PL and determine the weights of each indicator. The 60 items of original PLAQ was based on literature review and interviews, and administered to 1179 primary students graded 3–6 in China. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) are used to optimize the structure and verify the reliability and validity of the questionnaire. The model of PLAQ is composed of 4 first-level indicators, 10 second-level indicators and 35 third-level indicators. The results of EFA and CFA resulted in a 44-items, 4-factor questionnaire. EFA item loadings ranged from 0.558 to 0.896, and Cronbach’s alpha ranged from 0.818 to 0.892. The results of CFA show that the constructed model fits well, and PLAQ has good convergent validity and discriminative validity. The PLAQ appeared to be reliable and valid that can be used as an assessment tool for students in grades 3–6. PLAQ can be used as a guide for the development of PL. Additionally, PLAQ gives us a shared understanding about what PL is and how it can be developed by Chinese children. However, studies on the accuracy and generalizability of the PLAQ should be conducted to improve it in the future.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Invisible photonic prints shown by deformation are prepared by soaking the mechanochromic photonic paper with crosslinker (PEGDA) and subsequently crosslinking part of the paper through a photo ...lithography process. The key point of this new technique is creating patterns and background with very close photonic structures but different mechanochromic capabilities, so that the invisible photonic patterns in relaxed state can be revealed under deformation due to the nonuniform change in photonic structure. Based on the relationship between crosslinking level and the reflection changes during deformation, one can conclude that a low crosslinking level favors the hiding of invisible patterns and a high crosslinking level favors the showing of patterns. The as‐prepared samples can instantly and reversibly show the patterns by deformation and hide them by relaxation for many times, and the encapsulation by PDMS rubber prolongs its life time and enhances its durability in practical usages. The current printing technique is capable of creating invisible photonic prints in both macroscale and microscale range, which makes them potentially useful for security and antifraud applications in daily life.
An effective photonic printing method is developed to create patterns and background with very close photonic structures but different mechanochromic capabilities, so that the invisible photonic patterns in relaxed state can be revealed under deformation due to the nonuniform change in photonic structure. The patterns can be instantly and reversibly shown or hidden for many times, which could be a useful encryption or antifraud material in daily life.
Cushioning energy absorbing materials are developing towards lightweight and high specific strength. Therefore, how to ensure the lightweight and high strength of materials is an important issue of ...common concern to researchers. In this paper, a stretchable shear thickening gel/polyurethane foam composite material, with excellent shear hardening and energy absorption characteristics, was prepared by one-step foaming method. The strain rate sensitivity of the composite was 1.5-1.9 times than that of the pure polyurethane foam. Importantly, the addition of shear thickening gel increased the specific strength and specific energy absorption of the composite material by 82% and 96% respectively compared with pure polyurethane foam.
A SiO
colloidal photonic crystal film with a hierarchical porous structure is fabricated to demonstrate an integrated separation and colorimetric detection of chemical species for the first time. ...This new photonic crystal based thin layer chromatography process requires no dyeing, developing and UV irradiation compared to the traditional TLC. The assembling of mesoporous SiO
particles via a supersaturation-induced-precipitation process forms uniform and hierarchical photonic crystals with micron-scale cracks and mesopores, which accelerate the diffusion of developers and intensify the adsorption/desorption between the analytes and silica for efficient separation. Meanwhile, the chemical substances infiltrated to the voids of photonic crystals cause an increase of the refractive index and a large contrast of structural colors towards the unloaded part, so that the sample spots can be directly recognized with the naked eye before and after separation.
The blooms of coccolithophores are usually terminated by their viruses. However, little has been documented on the interplay between the host with virus under different environmental conditions. We ...investigated the relationship of
Emiliania huxleyi
(BOF92) and its virus (EhV99B1) after the coccolithophorid had acclimated to different levels of salinity (S35: 35‰; S25: 25‰) and CO
2
(AC: 400 μatm; HC: 1000 μatm) for about 15 generations. Our results showed that the virus infection decreased the growth of
E. huxleyi
along with decreased photochemical efficiency and photosynthetic carbon fixation under all the combinations of the treatments. Lowered salinity exacerbated the impacts of the viral infection on the growth and photosynthetic performance of
E. huxley
. The elevated
p
CO
2
appeared to have alleviated the impacts of the viral infection on its photosynthetic performance with enhanced levels of
F
v
/F
m
, by about 49% under S35 and by about 16% under S25, respectively. Nevertheless, the elevated
p
CO
2
enhanced the virus burst size by about 18% under the high and by about 46% under the low levels of salinity, respectively. It is concluded that reduced salinity under the elevated
p
CO
2
exacerbates the impact of the virus on
E. huxleyi
, leading to the highest burst sizes and the lowest photosynthetic carbon fixation, and the enhanced photochemical efficiency and increased levels of Chl
a
under the elevated
p
CO
2
could have facilitated the energy supply for the virus multiplication in the infected cells of
E. huxleyi
.
Photonic crystal (PC) pattern with angle-dependent colors is a promising anti-counterfeiting material as it can show unique visual effects without physical or chemical stimuli. Although various ...methods have been reported to fabricate PC patterns, few of them offer a complete solution for the fast, low-cost, and mass production of these materials. Here, delicate PC patterns are fabricated by silkscreen printing of photo-curable SiO
2
/monomer PC inks on the substrate, followed by ultraviolet irradiation to fix the PC structures. The PC inks composed of acrylic, acrylamide, and alkene monomers can be quickly cured in the air. They can also produce PC marks with noticeable angle effects, uniform color distribution, and good mechanical and chemical stabilities. Meanwhile, the silkscreen stencils with different mesh numbers are investigated to achieve the best color intensity and high printing resolution. Finally, as a demonstration of the anti-counterfeiting functions, the as-prepared monochromatic PC pattern changes color with the incident/viewing angle, while the bicolor pattern reversibly switches to a “quasimonochromatic” pattern or is alternately revealed under different angles.
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