Electro-optical coatings

This photoelastic stress analysis is a technique for the nondestructive determination of stress and strain components at any point in a stressed product by viewing a transparent plastic product. If not transparent, a plastic coating is used such as certain epoxy, polycarbonate, or acrylic plastics. This test method measures residual strains using an automated electro-optical system. 

This review will highlight the interrelationships between basic photopolymer science and practical applications of this technology. Each application of photopolymer technology can be described in terms of three primary descriptors the mode of exposure, the mechanism of the photopolymer reaction employed and the visualization method used. Using this foundation, the widely diverse applications of photopolymer technology to electronic materials, printing materials, optical and electro-optical materials, the fabrication of devices and polymeric materials, adhesives and coating materials will be discussed. 

Colloidal crysfals can be viewed as the mesoscopic counterpart of atomic or molecular crystals. They have been used to explore diverse phenomena such as crystal growth [52-54] and glass transition [55,56], and have many interesting applications for sensors [57], in catalysis [58,59], advanced coatings [60], and for optical/electro-optical devices for information processing and storage [61,62]. In particular, their unusual optical properties, namely the diffraction of visible light and the existence of a photonic stop band, make them ideal candidates for the development of photonic materials [61,63-66]. They may lead to the fabrication... 

The concept of local perturbations of the director around nanoparticles, often linked to homeotropic anchoring to the nanoparticle surface, is a concept often brought forward in discussions of thermal, optical and electro-optic properties of nanoparticle-doped nematic liquid crystals, which adds a slightly different perspective to the invisibility of smaller particles in aligned nematics. This appears to be of particular relevance for particles coated with either hydrocarbon chains or pro-mesogenic as well as mesogenic units. 

Yoshida et al. recently disclosed an alternative method that allowed them to produce stable suspensions of gold nanoparticles (1-2 nm in diameter) in nematic liquid crystals [315]. They used a simple sputter deposition process, which allowed them to prepare thin liquid crystal films of well-dispersed gold nanoparticles in both 5CB and E47 (available from Merck) with a nanoparticle size depending on the used nematic liquid crystal. Unfortunately, the authors did not provide any details on whether the nanoparticles were capped with a ligand or bare, non-coated particles, which makes it difficult to assess and compare the reported thermal as well as electro-optic data. However, very similar effects were found as a result of nanoparticle doping, including lower nematic-to-isotropic phase transition temperatures compared to the used pure nematics as well as 10% lower threshold voltages at nanoparticle concentrations below 1 wt% [315]. 

ICP thin films were used as driving electrodes for polymer-Dispersed Liquid-Crystals (PDLC) display devices. Liquid-crystalline-based display devices, which are commonly made of a liquid-crystal compound sandwiched between two substrates coated with a conducting layer of indium tin oxide (ITO), whose substitution with ICP electrodes could improve the optical and mechanical properties of the display devices. On the way to all-organic displays, PDLC sandwiched between two plastic substrates coated with ICP layers are promising devices for paper-like displays for electronic books which require flexibility, lightness, and low-power consumption. The electro-optical characteristics (transmission properties, drive voltages and switching times) of the PDLC devices depend on the nature of the ICP substrate used [13]. 

A electrooptic polymer crosslinked film was formed by spin-coating a 25 wt% of the Step 12 product in cyclopentanone onto an ITO covered glass slide. The solution was filtered through a 0.2 pm nylon filter, spin-coated at 500 rpm for 6 seconds and 1000 rpm for 30 seconds, and then soft baked at 50°C overnight under vacuum to give a 3.2 pm thick film. The film was corona poled with a needle at 20 kVand heated to 220°C for 5 minutes for crosslinking. The film was then cooled to ambient temperature under the applied field to give an electro-optic film with an raa of 36 pm/V at 1.31 pm. 

Okazaki, S., Uto, S., Ozaki, M., and Yoshino, K. Guest-host electro-optic switching m spin-coated polymer ferroelectric liquid crystal film. Appl. Phys. Lett. 71, 3373 (1997). 

Shevchenko Y, Blair D, Derosa M, Albert J (2008) DNA target detection using gold-coated tilted fiber Bragg gratings in aqueous media In Conference on lasers and electro-optics, CLEO-2008, San Jose, CA, 4- 9 May 2008, paper CMJ4... 

Spin-Coating and Thermal-Evaporating for Flexible Organic Light Emitting Diodes. Master thesis of Graduate Institute of Electro-Optical and Materials Science, National Formosa University. 

PAn-nitrilic rubber composites76 have been prepared using rubber-coated anodes for electyropolymerization. The resultant material has the mechanical properties of a crosslinked elastomer with the electrical and electro-optical properties... 

The properties and characteristics of films in the optical and electro-optical categories are discussed because these types constitute the most important applications of coatings on glass and plastics. Finally, some tables containing pertinent film data are appended. 

A wealth of information about photolumescent materials, their properties and conditions for their optimum preparation is found in [257]. In combination with glass substrates coated with transparent electrodes, the electro-optical properties of liquid crystal films, which themselves emit no light, offer some interesting possibilities [258, 259]. Liquid crystals have the mobility of liquids and the optical properties of solids. The molecular structure lies between the liquid and solid state. Liquid crystals are organic compounds of relatively long molecules compared with their diameter, and often contain polar groups and multiple bonds. 

Coatings on glass and polymers are found today in an increasing number ranging from the architectural and automotive sector, the diverse applications in technical and scientific optics to various sophisticated high-tech structures. Coatings are used in practically all optical and electro-optical devices. They are frequently the ultimate determinants of performance. 

A method to obtain nano-particles at air/water interfaces has been described in [287]. Spreading of surfactant-coated metallic, semi-conducting, magnetic and ferroelectric nanoparticles on water surfaces results in the formation of monoparticulate thick films which then can be transferred, layer by layer, to solid substrates. These films can find potential applications in advanced electronic and electro-optical devices. Here and further, we give only typical examples of using surfactants in novel technologies. A more detailed description can be found in a new edition of Surfactants Science Series [288]. 

As stated above, photopolymerizable systems have found utility in a wide range of fields, including for imaging, surface coatings and modifications, printed circuit boards and integrated circuits, and the fabrication of oriented crystalline materials for electro-optical applications. However, in recent years, photopolymerization is becoming a viable technique for... 

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