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Herein, we demonstrate an information encryption strategy based on multilayer quasi-amorphous photonic structures (QAPS) composed of alternating arrangements of high and low refractive index materials. The designs are created by alternately spraying monodisperse SiO2 and Fe3O4@SiO2 colloidal particles as well as CdSe/ZnS quantum dots (QDs) on a specific substrate, which can realize solvent/ultraviolet (UV) driven multiple information encryption and decryption. Due to the strong light scattering of the top SiO2 QAPS layer, the information stored in the lower Fe3O4@SiO2 layer is encrypted. After infiltration of the ethanol solvent into the voids of QAPS, the SiO2 layer becomes transparent due to the vanishing of refractive index contrast between SiO2 and ethanol, while the Fe3O4@SiO2 layer maintains bright structural color due to its high refractive index. At the same time, the information carried by QDs can be revealed under the excitation of UV light. Thus, this simple and reliable information hiding/displaying system, together with diverse encryption modes and convenient manufacturing process, makes it a potential security material to be applied in various fields.

Thermoresponsive smart windows (TRSWs) take great advantages in energy-efficient buildings and on-demand devices owing to their self-adaptiveness and external energy consumption-free nature. Currently used TRSWs largely rely on thermal-induced phase transitions in single-material systems, however, the intrinsic characteristics of which may not be suited for practical window utilization, such as poor luminous transparency and fixed critical temperature (T

Well-defined Fe3O4@SiO2 composite colloidal particles decorated with Ag nanoparticles were successfully synthesized through a simple chemical approach. These particles self-assembled into 1D chain-like photonic structures under the induction of magnetic field and diffract tunable structural colors. The hue and brightness of the structural colors are related to Ag nanoparticles deposited on the particles surface and its brightness increases with the increase of Ag concentration. This phenomenon could be the result of the superposition of photonic bandgap formed by photonic crystals and possible plasmonic property, as well as capability in absorbing stray light of Ag nanoparticles. As-prepared Fe3O4@SiO2@Ag colloidal particles have great potential to be applied in many crucial areas such as color displaying, biological detection and anti-counterfeiting technology.

Highly charged monodisperse magnetite/polystyrene colloidal particles are successfully synthesized by using a miniemulsion polymerization method. The particles, with high saturation magnetization (Ms ≈ 38.6 emu g−1), display high sensitivity to the magnetic field and can self-assemble into periodically ordered colloidal structure in aqueous solution, thus diffract light strongly, under magnetic induction. By changing the strength of magnetic field, the position of reflection peaks can be reversibly tuned in the range of 420–720 nm, covering almost the entire visible light range. After adding 1.5 wt.% of acid black 210 into the colloidal suspension, the color saturation and brightness of the colloids are significantly improved. As-prepared magnetically responsive colloidal particles have great potential to be used in color display, biosensors, anti-counterfeiting, camouflage, pigments and dyes.

Smart optical materials are drawing more and more attention because of their wide application in energy conservation, wearable sensors, optical tuning, and medical devices. However, current smart optical materials, including electroresponsive, thermoresponsive, and mechanoresponsive materials, are greatly restricted in practical applications because of their long response time, complicated preparation, and high cost. This study develops a novel, magnetically tunable, smart optical material with swift and high-contrast optical switching based on one-dimensional (1D) Fe3O4@SiO2 nanochains (NCs), which have the large shape anisotropy of the 1D structure and the superparamagnetic properties of Fe3O4 particles. The material exhibited a clear transparent state when NCs were arranged parallel to the viewing direction under an applied magnetic field, whereas it showed good shielding effect when the NCs were randomly oriented upon removal of the field. The light transmittance could be dynamically adjusted over the wide range of 20-80% through a small applied magnetic field of 50-100 Oe, which is superior to most of the currently reported systems. This swift, sensitive, and reversible response is attributed to the good responsivity of magnetic NCs. Also, an effective model was proposed to explain the transmittance modulation scheme and forecast its optical potential. The large tunable range and the low triggered field make Fe3O4@SiO2 NCs an advantageous candidate for application in smart windows, optical switchers, and other fields.

Quaternized chitosan (QCS) was prepared and its interface behavior on cellulosic substrates was investigated. FT-IR result indicated that quaternary ammonium groups were connected to -NH2 in chitosan, and the highest degree of substitution (DS) of QCS was 80.0 %. The adsorption behavior of QCS was well performed on cellulosic substrates. The initial critical concentrations of QCS were between 10 mg/l and 20 mg/l, which were related to its DS and the weight average molecular weight (M w ): the critical concentration decreased with the increasing DS of QCS, and the concentration increased when M w increased. The results from SEM and particle size revealed that the flocculation took place mainly because the electrostatic interaction between cellulosic substrates and QCS, which can be accelerated by forming a charge patch. At last, QCS displayed high efficiency as a retention and drainage-aid agent through a Schopper-Riegler beating degrees tester.

The preparation of cellulose laurate was investigated through transesterification in 1-allyl-3-methylimidazolium chloride (AmimCl)/dimethyl sulfoxide (DMSO) cosolvent system by using vinyl laurate as an acylation reagent and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as an effective catalyst. The effects of reaction temperature, reaction time and the molar ratio of vinyl laurate to anhydride glucose unit (AGU) were investigated. The degree of substitution (DS) ranged from 1.47 to 2.74 under the selected conditions and the reaction order of three hydroxyl groups was C-6 > C-3 > C-2. The chemical structure cellulose laurate were explored by Fourier transform infrared (FT-IR) spectroscopy, 1H-nuclear magnetic resonance (NMR), 13C NMR, heteronuclear single quantum correlation (HSQC) and X-ray diffraction (XRD) to confirm the occurrence of transesterification. The improved thermal stability of cellulose laurate was proved by the thermogravimetric analysis (TGA). The tensile analysis and the contact angle measurement confirmed the ductile behavior and the hydrophobicity of the films made from cellulose laurate.