Applications and Future Trends

Practical applications of photochromism at first (ca. 1955-70) concentrated on the spiropyrans, and especially on BIPS compounds, because of their ready availability, photosensitivity, convenient thermal fade rates, and good color contrast when perceived by the human eye. However, applications in which the dye was required to cycle very many times (e g., an optical binary switch for a photochemical computer memory) or be irradiated continuously (e g., sunglasses, vehicle windshields) were impractical because of the rapid fatigue of these dyes.196 

One recent trend has been away from using a photochromic dye itself merely as an individual component of a solution, polymer film or bulk polymer matrix. Instead, the photochromic is chemically linked to a polymer, which may be a natural polymer such as a cellulose derivative, an enzyme, a protein, or synthetic polymers from acrylates, urethanes, and vinyl compounds. The properties of the polymer can then be modified by external irradiation, and conversely, the properties of the photochromic are modified by the polymer. A recent biochemical example is the photocontrolled binding of monosaccharides to concanavalin A (Con A) modified with spiropyran units.208 

Photochromic control of the polymer properties leads to potential applications involving the mechanical properties of a solution (viscosity, photogelation), polymer fiber (extensibility, photomuscle ), or membrane (porosity). More important, however, the ability to control the activity of enzymes and other biologically important macromolecules leads to potential applications in clinical phototherapy. 

In the future, spiropyrans most likely will be used chiefly in biochemistry and image technology or optical physics, in ways in which their inherent fatigue can be neglected (not overcome - merely neglected). The potential applications of properly designed spiropyrans as biosensors specific for cations and nucleotides has already been described. 

Spiropyrans show promise for optical recording, three-dimensional optical memories,214 and holography.215 The dyes currently under study for these applications very probably will not be used merely dissolved in a bulk polymer matrix, but will be oriented in films and membranes, or adsorbed or vapor deposited on solid substrates to take advantage of the nonlinear optical properties of the colored forms. For example, thick (0.5 mm) PMMA films of 6-nitro-thiaBIPS can be used to record wavelength-multiplexed volume holograms with an infrared diode laser. This system is impractical at present because of fatigue and poor diffraction efficiencies.216 

Wet spinning methods are also being explored by fiber scientists to develop conducting polymer fibers. Continuous poly(3,4-ethylenedioxythiophene) p oly(styrenesulfonate) (PEDOTPSS) fibers were produced by using a simplified wet spinning process. Optimum wet spinning conditions were shown to produce fibers with good mechanical and electrical properties. The fiber 

In conclusion, wet spinning is a comparatively cost-effective production method. The drawbacks of low spinning speeds have recently been eliminated. Additionally, recent developments have shown that wet-spun fibers have wide application in the area of high-tech textiles. 

Gupta and V. K. Kothari (1997), Manufactured Fiber Technology, Chapman and Hall, London, UK. 

Chavan and A. K. Patra (2004), Development and processing of lyocelP, Indian Journal of Fiber and Textile Research, 29, December, 483-492. 

Woodings (Ed.) (2001), Regenerated Cellulose fihm, Woodhead Publishing 

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Aqueous micellar solutions of many nonionic surfactants, with an increase in temperature, become turbid over a narrow temperature range, which is referred to as their cloud-point [17,277]. Above the cloud-point temperature, such solutions separate into two isotropic phases. Cloud-point extraction (CPE) is also referred to as a particular case of ATPE [278,279] and more specifically as aqueous micellar two-phase systems [10,277]. Very recently, in an extensive review, Quina and Hinze [280] have discussed in detail the emergence of CPE as an environmentally benign separation process, highlighting the basic features, experimental protocols, recent applications, and future trends in this area. 

Pulsatile Drug Delivery Current Applications and Future Trends Gurny, R., Junginger, H.E., Peppas, N.A., Eds. Wissenschaftliche Verlagsgesellschaft Stuttgart, Germany, 1993. 

Nanotechnology-Enhanced Orthopedic Materials Fabrications, Applications and Future Trends... 

Nanotechnology-enhanced orthopedic materials Fabrications, applications and future trends... 

Lopes, A.C., Martins, P., Lancetos-Mendez, S. Aluminosilicate and aluminosilicate based polymta- composites pesent stams, applications and future trends. Prog. Surf. Sci. 89, 239-277 (2014)... 

This chapter provides an extensive overview concerning the effects of thermal degradation on various biopolymer based nanocomposites. It discusses the most recent developments/findings in relation to biopolymer based nanocomposites, in particular the effects of different nanoparticles on the thermal stability. Other issues regarding the research challenges, applications and future trends are also addressed in this chapter. 

Pultrusion is one of the fastest growing processes within the industry for manufacturing composite products. The developments such as standards available to date, global market scenario, novel applications and future trends of the pultrusion industry are of interest to composite manufacturers and researchers. 

E. M. Fernandes, R. A. Pires, J. F. Mano, and R. L. Reis, Bionanocomposites from lignocel-lulosic resources Properties, applications and future trends for their use in the biomedical field. Progress Polym. Sci. 38(10-11), 1415-1441 (2013). 

Quijano, G., Couvert, A., and Arrrrane, A. (2010) Ionic liquids applications and future trends in bioreactor technology. Bioresour. Technol., 101, 8923-8930. 

Jackson, Chung, Calundann and East and others have given extensive reviews of the development, applications and future trends of LCP technology. Table 9.2 summarizes some applications pointed out by the Hoechst-Celanese Corporation. Hoechst-Celanese estimates the market for thermotropic LCPs in the mid-1990s to be 73% consumer, 8% industrial, 5% electrical/electronics, 5% telecommunications, 4% transportation, 3% aircraft/aerospace and 2% other. ... 

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