光致变色针织功能面料的制备及颜色响应性能

光致变色纺织品由于其优异的可逆变色性能和优异的物理性能,在很多高新技术领域都有潜在的应用,因此受到越来越多的关注.为了提高光致变色敏感性,文中设计合成两支不同碳链长短的新型螺吡喃光致变色功能染料,将这些染料通过高温高压染色上染涤纶针织物,获得了具有光致变色功能的针织功能面料.通过紫外-可见吸收光谱,研究了其在溶液中的光...     

Temperature-dependent behavior of Langmuir monolayers of an amphiphilic spiropyran

The effect of subphase temperature on behaviors and morphologies of an amphiphilic spiropyran, 1′,3′-dihydro-3′,3′-dimethyl-6-nitro-1′-octadecyl-8-docosanoyloxymethylspiro[2H-1-benzopyran-2,2′[2H]indol] onto pure water was investigated by measurements of surface pressure–area isotherms and Brewster angle microscopy, respectively. Both depend strongly on the subphase temperature. The isotherms at 30 °C show a distinct phase transition at 7.5 mN m⁻¹, while no such phase transition is observed at 7 °C. The morphology changes drastically accompanying the phase transition at 7.5 mN m⁻¹, at which many large circular domains are formed. Furthermore, we have demonstrated that the morphology changes reversibly accompanying appreciable hysteresis in the isotherms upon continuous compression and expansion cycles.     

Liquid crystalline siloxanes containing spiropyran chromophores as reversible optical data storage materials

The application of liquid crystalline siloxanes consisting of pentamethylhydrocyclosiloxane cores with attached cholesteryl-, biphenyl- and photochromic spiropyran-based mesogens as reversible optical data storage materials is demonstrated by grating formation with an argon ion laser beam operating in the UV and visible regions. Erasure of the gratings with heat or visible radiation was possible.     

真空蒸发沉积18烷基取代螺吡喃薄膜的光致变色及光电子谱研究

利用真空蒸发的方法在玻璃载片上沉积了 18烷基取代螺吡喃薄膜 ,并利用光吸收谱和光电子谱研究了薄膜的光致变色特性及变色前后分子结构的变化情况。实验结果发现 ,真空蒸发沉积的 18烷基取代螺吡喃薄膜具有良好的光致变色性能 ,在紫外光的照射下可以发生明显的光致变色反映。光电子谱分析 :经紫外线照射后 ,N1s、O1s光电子峰发生明显的变化 ,说明经紫外线照射后分子结构发生了变化 ,导致分子内部电荷的重新分布。另外紫外线照射后氧含量增加 ,这是因为紫外线照射后薄膜表面对水汽的吸附能力增加所致     

The theoretical study of substituent and charge effects in the conformational transformation process of molecular machine unit spiropyran

Besides the photochromism isomerization, the impact of the electrochemical conditions on the spiropyran/merocyanine (SP/MC) isomerization process is also getting more and more attention. In a certain electrochemical cell, spiropyran reduced to form a radical anion and the SP/MC isomerization becomes spontaneous. Therefore, thermal reaction mechanisms for the neutral, cationic and anionic SP/MC isomerization with a series of electron-donating and electron-withdrawing groups in the 6- position of the benzopyran moiety in ground state have been systematically investigated using the density functional theory method. Some notable changes in structure, activation energy barrier and reaction rate caused by charge changes of spiropyran have been found and discussed in detail. For anionic SP/MC isomerization, due to the electron density distribution changed, the activation energy barriers decreased and the reaction rate constants of every step increased greatly. The geometrical parameter, bond length alternation (BLA), which relates to the effect of substituents, has been employed to explain the changes in the reaction mechanism induced by different electron-donating and electron-withdrawing substituents. Our results explained the control method of the small unit of the molecular machine conformational transformation process deeply from the theoretical viewpoint.     

Cyclodextrin effects on the photochromism of spiropyrans/β-cyclodextrin inclusion polymers

A series of photochromic polymers were prepared by forming inclusion complexes of various spiropyrans (SPs) in the cyclodextrin cavities of the β-cyclodextrin polymer (CDP). Experimental and calculation results demonstrate that the hydrophobic β-CD cavities can encapsulate the studied SPs from an aqueous solution and form 1:2 SP/β-CD inclusion complexes. The complexes undergo reversible photoinduced isomerization from a colorless closed form with absorption maxima (λ_expt) at 297–359 nm to a colored open-form photomerocyanines (PMs) with absorption maxima at 547–618 nm. For the less polar closed-form SPs, the β-CD cavity behaves similarly to toluene, providing a hydrophobic environment, and thus the λ_expt of the inclusion complexes of SPs with the β-CD in CDP is increased compared with that of ethanol solutions of the SPs. However, the structure effects from the steric hindrance of the β-CD cavity reduce the energy gap of excitation and further increase the λ_expt of SPs. For zwitterionic open-form PMs, the hydroxyl groups, laced on the rims of β-CD, act similarly to ethanol. The interaction effects from the hydroxyl groups simultaneously lower the ground- and excited-state energy of the SPs. The competing effects between the structure and interaction factors cause changes in the λ_expt of SPs.