Light-sensitive polymers

11 General structure of a light-sensitive leuco derivative (adapted from Irie and Kunwatchakun 1986). 

A useful method of combining polymers and light sensitivity is through use of polymer micelles. By incorporating hydrophobic photosensitizers within the core of the micelle, the system can then be utilized for photodynamic therapy (PDT) 

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A need for single-phase polymers in some applications, e.g., polytetrafluoroethylene, VHMWPE, light-sensitive polymers, etc. 

Irradiation at >320 nm releases from the polymer, whether insoluble or water-soluble, free oligosaccharides in very high yields. A simple illustration of such a sequence carried out with either insoluble 2-aminoethyl-substituted poly(acrylamide) beads or with water-soluble, substituted poly(vinyl alcohol) is presented in Scheme 9 the isolated overall yield of lactose was 29.9% (soluble-polymer approach). The synthesis on light-sensitive polymers facilitates the isolation of products, which is important from the preparative point of view and as a tool for the study of enzymes, permitting efficient comparison of acceptor specificity and being capable of demonstrating de novo synthesis. 

Wiemann T, Taubken N, Zehavi U, Thien J, Enzymic synthesis of N-acetyllactosamine on a soluble, light-sensitive polymer, Carbohydr. Res., 257 C1-C6, 1994. 

Photolithography—A method of integrated circuit fabrication that uses a light-sensitive polymer to pattern a silicon wafer with other materials. 

This is a light sensitive polymer (X max. 265 nm), but it has high heat resistance. For this reason, pyrolysis was performed at 850° C in He. Other conditions were kept similar to those for other examples previously described in this book (see Table 4.2.2). The separation was done on a Carbowax column. The pyrogram is shown in Figure 13.4.1. The peak identification was done using MS spectral library searches only and is given in Table 13.4.3. 

The three most important parameters which must be controlled when comparing the photographic speeds of similar negative-woiking-light-sensitive polymers are the following ... 

Para-Sexiphenyl Layers Grown on Light Sensitive Polymer Substrates... 

J.L.R. Williams, Fortschritte der chemischen Forschung, Springer Verlag, Berlin, Bd 13(2), pp. 227 250 (1969) G.A. Delzenne, S3mthesis and photocrosslinking of light sensitive polymers, Fur. Polym. J., Suppl., pp. 55 91 (1969) G.A. Delzenne, Photocrosslinkable polymeric systems and their technical applications, Makromol. Chem., Suppl. 2, 169 188 (1979). 

The production of modem printing plates involves photopolymerization or photo-crossiinking of light sensitive polymers called photoresists to solubilize or insolubize the exposed area, depending on the kinds of resists used, followed by development and etching. The fast drying of wet ink films can be accomplished by exposure to u.v. or electron beams which photochemically initiated rapid photopolymerization of the wet ink to solid patterns... 

Kataoka and coworkers recently evaluated the importance of the PEG corona for photodynamic therapy and verified the dependence of light-sensitive polymers on primary tumor accumulation [144]. A porphyrazine derivative was encapsulated in BVqMAA copolymers (polybutadiene-block-poly(l-methyl-2-vinyl pyridinium methyl sulfate)-block-poly(metacrylic add)). The nanoparticles were then PEGylated by electrostatic interaction between MAA and the poly-L-Lysine PEG copolymer. This resulted in better stability in blood, tumor accumulation and tumor regression after irradiation of PEGylated porphyrazine-loaded micelles over im-PEGylated micelles. 

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