Superchiral light, generated by the interference of two counter-propagating circularly polarized light (CPL) with same frequency, opposite handedness and different intensity, exhibits enhanced dissymmetry in its interaction with chiral molecules, and has the potential for ultrasensitive detection and characterization of chiral molecules. It is anticipated that the enhanced optical dissymmetry in superchiral light (SCL) field may be utilized to promote asymmetric photochemical reactions efficiency. Herein we reported SCL impart greater chiral bias to trigger asymmetric photo-polymerization reaction from initially achiral diacetylene (DA) monomer, and the enhanced optical dissymmetry for whole polydiacetylene (PDA) films could be achieved. An explanation based on the chiral transfer and amplification of chiral bias from SCL during the polymerization process has been proposed. Moreover, thus formed chiral PDA films polymerized by SCL exhibited enhanced enantioselective recognition ability, and can serve as a direct visual probe for the discrimination of some specific enantiomers.

Poly(N‐isopropylacrylamide)‐block‐poly{6‐[4‐(4‐methylphenyl‐azo) phenoxy] hexylacrylate} (PNIPAM‐b‐PAzoM) was synthesized by successive reversible addition‐fragmentation chain transfer (RAFT) polymerization. In H2O/THF mixture, amphiphilic PNIPAM‐b‐PAzoM self‐assembles into giant micro‐vesicles. Upon irradiation of light at 365 nm, fusion of the vesicles was observed directly under an optical microscope. The real‐time fusion process is presented and the derivation is preliminarily due to the perturbation by the photoinduced trans‐to‐cis isomerization of azobenzene units in the vesicles.magnified image

A series of side-chain polymer liquid crystals (PLCs) of 6-[4-(4-ethylphenyl)diazenylphenyloxy]hexyl methacrylate and 4′-[6-(methacryloyloxy)hexyloxy]-4-cyanobiphenyl were synthesized and characterized. The effects of contents of the azo units and the wavelength of irradiation light on photoinduced alignment behavior were investigated. On irradiation of linearly polarized light (LPL) at 366 nm directly, alignment change was induced only in the PLC with 6 mol % azo units (P6), while phase transition took place in the other PLCs with higher contents of the azo units. On irradiation of LPL at 436 nm directly, alignment was induced with a fair efficiency in P15 and P35, low efficient alignment was observed in P6 and P100, and no alignment change was induced in P55 and P75, which exhibited a homeotropic state. A high alignment efficiency was achieved in all PLCs by using another method: irradiation with 366 nm unpolarized light at first and then with 436 nm LPL. The alignment change induced by this method was explored at various temperatures. All-optic switching might be realized by irradiation of 336 nm unpolarized light and 436 nm LPL alternatively based on the photochemical phase transition and the photoinduced alignment processes of the PLCs, respectively.

We demonstrate a new strategy for improved stabilization of polydiacetylene micelles. They show temperature-induced color changes, which are fully reversible even at varying pH. A novel azo chromophore-functionalized amphiphilic diacetylene molecule is synthesized and used to prepare self-assembled cylindrical micelles. The micelles can be polymerized by 254 nm light irradiation. The azo chromophores form H- and J-like aggregates in the polydiacetylene micelles and increase the stability of the micelles, which leads to fully reversible thermochromism of the micelles in the temperature range between 20 and 90 °C and the pH range between 5.6 and 9.6.

Micro-electron diffraction measurements were obtained with a different TEM instrument that is not ªhigh-resolutionº, therefore diffraction from an individual crystallite is not presented with the corresponding image.

We report herein the development of a highly robust, quantitative, sensitive, and naked eye colorimetric detection method for different isomers of aromatic compounds using β-CD-modified silver nanoparticle (AgNPs) probes. This assay relies on the distance-dependent optical properties of Ag nanoparticles and the different inclusion binding strength of the aromatic guests to β-CD host. In the presence of different isomers of aromatic compounds, AgNPs could be rapidly induced to aggregate, thereby resulting in apricot-to-red color change. The variety and concentration of different isomers of aromatic compounds could be determined by monitoring with the naked eye or a UV-vis spectrometer. The present detection limit for different isomers of aromatic compounds is 5 × 10(-5) M. We believe that the surface architectures of AgNPs after the introduction of the CD-based host-guest recognition would be applicable for a range of chemical and bioanalytical molecular sensing systems in aqueous media.

By introducing methanol as a co-solvent into cyclopentanone, solvent effects on structure, photoresponse and speed of gelation of a dicholesterol-linked azobenzene organogel DCAZO2 have been investigated. Optical microscopy (OM) and scanning electron microscopy (SEM) images reveal that the gel fibers form macroscopic aggregates by adding methanol. Minimum gelation concentration (MGC) of the gels decreases with increasing methanol content, while the gel-to-sol transition temperature (T gel ) decreases firstly and increases afterwards. For photoisomerization (corresponding to gel-sol transition), the first stage rate constant k g1 of the gels decreases with increasing methanol content. The photoisomerization process of the gel with 5% methanol is different from the other five samples, whose first stage rate constant k g1 is greater than its second stage rate constant k g2 . By increasing methanol content from 0% to 30%, gelation time (corresponding to sol-gel transition) of both heated gel and UV-visible light irradiated gel decreases from 7 h to 5 min and 6 h to 0 min (before visible light irradiation is accomplished), respectively. Solubility parameters and Teas plots of the gelator and mixed solvents are systematically calculated to estimate the gelator-solvent interaction. It is found that gelation requires that the gelator-solvent interaction be neither too strong nor too weak, otherwise solution or precipitate are formed.

We demonstrate the realization of a coherent random fiber laser (RFL) in the extremely weakly scattering regime, which contains a dispersive solution of polyhedral oligomeric silsesquioxanes nanoparticles (NPs) and laser dye pyrromethene 597 in carbon disulfide that was injected into a hollow optical fiber. Multiple scattering of polyhedral oligomeric silsesquioxanes NPs greatly enhanced by the waveguide confinement effect was experimentally verified to account for coherent lasing observed in our RFL system. This Letter extends the NPs-based RFLs from the incoherent regime to the coherent regime.