Shape light-induced

Lendlein, Andreas, Hongyan Jiang, Oliver Jiinger, and Robert Langer. Light-Induced Shape-Memory Polymers. Nature 434 (April 14, 2005) 879-882. The researchers report the discovery of a shape-memory polymer that is responsive to light. 

Petrov, Peter G., Light-Induced Shape Transitions of Giant Vesicles, 6, 335. 

When the donor and acceptor are sufficiently close, as in an ion pair or in covalently linked complexes, electron transfer can be promoted by the absorption of light. An absorption band corresponding to the light induced electron transfer is usnally called a charge transfer (CT) absorption band . The molecnlar parameters that determine the CT absorptivity, bandwidth, and band shape are the same molecular parameters that determine the magnitude of the electron-transfer rate constant.In the weak-coupling limit, the absorptivity of the CT absorption band is small (much less than 10 cm ) in the strong-... 

The qualitative reaction profile given in Fig. 11 shows how a light-induced single-electron transfer process can be coupled to suitable follow-up steps to facilitate the formation of permanent two-electron photoredox products. Larger bond and shape reorganizations of excited state molecules, which typically involve the population of CT states or the formation of Jahn-Teller distorted species, are very helpful to achieve such... 

Smooth muscles derive their name from their appearance when viewed in polarized light microscopy in contrast to cardiac and skeletal muscles, which have striations (appearanee of parallel bands or lines), smooth muscle is unstriated. Striations result from the pattern of the myofilaments, actin and myosin, which line the myofibrils within each muscle cell. When many myofilaments align along the length of a muscle cell, light and dark regions create the striated appearance. This microscopic view of muscle reveals some hint of how muscles alter their shape to induce movement. Because muscle cells tend to be elongated, they are often called muscle fibers. Muscle cells are distinct from other cells in the body in shape, protein composition, and in the fact that they are multi-nucleated (have more than one nucleus per cell). 

It should be noted that the observed light-induced ESR signal of dyes was sharp and lacked any hyperfine structure. The signal, which was broad and Gaussian in shape at liquid nitrogen temperature, became sharper as the temperature of the ESR measurement was increased, and was Lorentzian in shape at room temperature. 

The reviewed results show that since the first demonstration of the photo-induced anisotropy in supramolecular complexes in 2005 and SRGs in 2006 the field has attracted much attention. The appeared works clearly demonstrated the eligibility of the supramolecular approach for light-induced processes and outlined the possibilities of material design. The achieved values shape very positive prospects for optical application. It can be expected that systematic studies will result in further improvement of the effects. 

Lendlein A, Jiang H, Jiinger O, Langer R. 2005. Light induced shape memory polymers. Nature 434 879 882. 

Lambeth RH, Moore JS. 2007. Light induced shape changes in azobenzene functionalized pol5uners prepared by ring opening metathesis pol5merization. Macromolecules 40 1838 1842. 

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