Photosensitive coating

Major polymer applications aerospace, electronics (mostly films and coatings), photosensitive materials for positive imaging, solar cells, hollow fiber membranes, composites. unclear power plants, space shuttle, microprocessor chip carriers, structural adhesives... 

Uses Photoinitiator for resist inks, dry film, coatings photosensitive resin additive intermediate for org. synthesis Manuf./Distrib. Aldrich http //www.sigma-aldrich.com-, Lancaster Synthesis Polymona Enterprise http //www. chemhunting. com-, Sumitomo Seika Suny Chem. Int l. http //www.sunychem. com TCI Am. http //www.tciamerica.com Trade Name Synonyms Runtecure 1093 [Runtec http //www.runtec-chem.com] Tribromoneopentyl alcohol CAS 1522-92-5 36483-57-5 Synonyms 2,2-Bis (bromomethyl)-3-bromo-1-propanol TBNPA 2,2,2-Tri-(bromomethyl) ethanol... 

Fig. 1. The hthographic process. A substrate is coated with a photosensitive polymer film called a resist. A mask with transparent and opaque areas directs radiation to preselected regions of the resist film. Depending on resist characteristics, exposed or unexposed portions of the film are removed using a developer solvent. The resulting pattern is then transferred to the substrate surface and the resist is stripped.

Poly(vinyl cinnamate) Resists. Dichromated resists exhibit numerous shortcomings which include lot-to-lot variabiUty of the components, aging of the formulated resists in solution and in coated form, poor process stabiUty (due to a sensitivity to variations in temperature and humidity), and intrinsically low photosensitivity requiring long exposure times for adequate insolubilization. 

Substituted Hydantoins. 5-Methylhydantoin [616-03-5] has been selected from several stmctures as a formaldehyde scavenger for color photosensitive materials and water-thinned inks and coatings (102,103). 

Resists. Resists are temporary, thin coatings appHed to the surface of the copper-clad laminate. After patterning, these films act as masks that are chemically resistant to the cleaning, plating, and etching solutions used to define the circuit traces of the PWB. Both nonphotosensitive and photosensitive types are used. 

Photopolymerizable coatings relief-image-forming systems, 6,125 Photoreactivity environmental effects, 1, 394 Photoredox properties bipyridyl metal complexes, 2, 90 Photoresist systems, 6,125 Photosensitive materials, 6, 113 Photosynthesis anoxygenic, 6, 589 magnesium and manganese, 6, 588 water decomposition models, 6, 498... 

Get the light into the detector. This may sound trivial, but unless a good anti-reflection coating is used, a significant fraction of the light will be reflected at the surface of the photosensitive material. 

Tricot, Y.-M. and Fendler, J.H., Colloidal catalyst-coated semiconductors in surfactant vesicles In situ generation of Rh-coated CdS particles in dihexadecylphosphate vesicles and their utilization for photosensitized charge separation and hydrogen generation, /. Am. Chem. Soc., 106, 7359,1984. 

Baugh and co-workers exposed solutions of phenylbutazone to the light of a projector lamp in the presence of typical dyes used to colour sugar-coated tablets. Erythrosine sodium photosensitized decomposition of the drug via, it was suggested, singlet oxygen [134]. 

For UV and visible radiation, the simplest detector is a photomultiplier tube. The cathode of the tube is coated with a photosensitive material (such as Cs3Sb, K CsSb, or Na2KSb, etc.) which ejects a photoelectron when struck by a photon. This photoelectron is then accelerated towards a series of anodes of successively greater positive potential (called dynodes). At each dynode, the electron impact causes secondary electron emission, which amplifies the original photoelectron by a factor of 106 or 107. The result is a pulse of electricity of duration around 5 ns, giving a current of around 1 mA. This small current is fed into the external electronics and further amplified by an operational amplifier, which produces an output voltage pulse whose height is proportional to the photomultiplier current. 

Negative two-layer resist. A cresol novolac resin (Alnovol PN-430) was spin-coated on a silicon wafer and baked at 80V, for one minute on a hot plate. The silicon wafer was set on a spin-coater and a photosensitive solution consisting of D1 (3 wtlfc), PVP (5 wt%), acetic acid (46 wt%), and water (46 wt%) was... 

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