Crystallinity transparency

Nomura, K. Ohta, H. Ueda, K. Kamiya, T. Hirano, M. Hosono, H. 2003. Thin-film transistor fabricated in single-crystalline transparent oxide semiconductor. Science 300 1269-1273. 

A third reason for interest in copolymers is crystallinity. Transparency and translucency are greatly affected by crystalline properties, which can be regulated by copolymerizatiOn. "... 

Colorless and odorless gas refractive index 1.000036 at 0°C and 1 atm density of the gas at 0°C and 1 atm 0.1785 g/L density of hquid hehum at its boihng point 0.16 g/mL liquefies at -268.93°C sohdifies at -272.2°C (at 26 atm) to a crystalline, transparent and almost invisible sobd having a sharp melting point cannot be solidified at the atmospheric pressure except by lowering temperatures critical temperature -267.96°C critical pressure 2.24 atm critical volume 57cm3/mol very slightly soluble in water solubility in water 0.0285 mg/L (calculated) at 25°C or 0.174 mL/L at NTP insoluble in ethanol. 

T. Ogi, D. Hidayat, F. Iskandar, A. Purwanto, K. Okuyama Direct synthesis of highly crystalline transparent conducting oxide nanoparticles by low pressure spray pyrolysis. Adv. Powder Technol. 20 (2), 203-209 (2009). 

Finally, the nature of the crystalline microstmcture, ie, crystal size and morphology and the textural relationship among the crystals and glass, is the key to many mechanical and optical properties, including transparency/opacity, strength and fracture toughness, and machinabiUty. These microstmctures can be quite complex and often are distinct from conventional ceramic microstmctures (6). 

Thin films (qv) of lithium metal are opaque to visible light but are transparent to uv radiation. Lithium is the hardest of all the alkaH metals and has a Mohs scale hardness of 0.6. Its ductiHty is about the same as that of lead. Lithium has a bcc crystalline stmcture which is stable from about —195 to — 180°C. Two allotropic transformations exist at low temperatures bcc to fee at — 133°C and bcc to hexagonal close-packed at — 199°C (36). Physical properties of lithium are Hsted ia Table 3. 

Microscopes are also classified by the type of information they present size, shape, transparency, crystallinity, color, anisotropy, refractive indices and dispersion, elemental analyses, and duorescence, as well as infrared, visible, or ultraviolet absorption frequencies, etc. One or more of these microscopes are used in every area of the physical sciences, ie, biology, chemistry, and physics, and also in their subsciences, mineralogy, histology, cytology, pathology, metallography, etc. 

Optical Properties. Owing to the high crystallinity of HDPE, most thick-waHed articles made from HDPE resins are opaque. Significant surface roughness can also add to the opacity. Thin HDPE film, in contrast, is translucent, but its transparency is significantly lower than that of LDPE or LLDPE film. The ultraviolet transmission limit of HDPE is around 230 nm. 

Pure amorphous polymers, being homogeneous materials, are transparent. Atactic polystyrene is a good example. The crystalline syndiotactic form is not transparent. Alack of transparency does not necessarily indicate crystallinity, however. It can also be caused by inorganic fillers, pigments, gas bubbles (as in a foam), a second polymer phase, etc. 

In addition to conferring transparency on these polymers, the amorphous noncrystaUizable nature of polysulfones assures minimal shrinkage during fabrication of the resins into finished parts. The absence of crystallinity also assures dimensional stabiUty during the service life of the parts where high use temperatures are encountered. Good dimensional stabiUty is important to many stmctural and engineering appHcations. 

Figure 4 shows the basic constmetion of the devices used in different appHcations, involving the deposition of multilayers of i -SiH of intrinsic (/), doped ), and closely aUied films, such as amorphous siHcon nitride, SiN, and transparent conducting oxide (TCO). As in crystalline... 

Sodium thiosulfate, either the anhydrous salt, Na2S202, or the crystalline pentahydrate, is commonly referred to as hypo or crystal hypo. When a concentrated sodium thiosulfate solution (50—60 wt %) is cooled to <48° C, the pentahydrate, containing 63.7% Na2S202, crystallines in monoclinic transparent prisms as shown in the equiUbrium phase diagram (Fig. 1). The monohydrate [55755-19-6] and the heptahydrate [36989-91-0] are also known. 

Copolymerisation also affects morphology under other crystallisation conditions. Copolymers ia the form of cast or molded sheets are much more transparent because of the small spheruHte size. In extreme cases, crystallinity cannot be detected optically, but its effect on mechanical properties is pronounced. Before crystallisation, films are soft and mbbery, with low modulus and high elongation. After crystallisation, they are leathery and tough, with higher modulus and lower elongation. 

Polycarbonates. Polycarbonates (qv) are pardy crystalline thermoplastics with some disorder in the crystalline part and considerable order in the amorphous part. This disorder conveys high impact strength which, combined with its good transparency and outdoor exposure resistance, makes polycarbonates usefiil for vandal-resistant glazing and outdoor lighting. It is easily processed by extmsion and injection mol ding. Various uv and dame-retardant agents are often added. 

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