Crystal solution-grown

Preparation of solution-grown crystals (including so-called single crystals ) of linear polymers [2-4,8,10-13]... 

Figure 12 shows that the fold of the 110 sector yields stems inclined to the lamellar normal. Regular folds have been identified in solution-grown crystals by infrared spectroscopy from the detailed spectrum of the CH2... 

The solution-grown crystal (SGC) from dilute solution forms diamond-like crystals of lateral dimension up to several micrometres, but their thickness is about 10 nm in which polymer chains are folded. The chain axes are parallel to the thickness direction of these lamellar crystals. In SGC materials precipitated from dilute solutions (Figure 3A), the lamellae are stacked and oriented parallel to the material surface. 

Figure 18. (a) CH2 and (b) CD2 deformation bands in the IR spectrum of extended-chain solution-grown crystals of end-labeled n alkane Ci2D25Cig2H384Ci2D25. The sample was annealed at the temperatures indicated (in °C) and the spectra recorded at 110 K (from ref 103). 

Different exposed crystal surface planes have different relative reactivities. The flat growth surfaces of solution-grown crystals tend to retain small irregularities, due to uneven development and accumulation of impurities during removal of last traces of solvent. (Surfaces may also be damaged during handling.)... 

KNs. The d.c. electrical conduction of KN3 in aqueous-solution-grown crystals and pressed pellets was studied by Maycock and Pai Verneker [127]. The room-temperature conductivity was found to be approximately 10" (ohm cm) in the pure material. Numerical values for the enthalpies of migration and defect formation were calculated from ionic measurements to be 0.79 0.05 and 1.43 0.05 eV (76 and 138 kJ/mole), respectively. In a subsequent paper [128], the results were revised slightly and the fractional number of defects, the cation vacancy mobility, and the equilibrium constant for the association reaction were calculated. The incorporation of divalent barium ions in the lattice was found to enhance the conductivity in the low-temperature region. Assuming the effect of the divalent cation was to increase the number of cation vacancies, the authors concluded that the charge-carrying species is the cation, and the diffusion occurs by means of a vacancy mechanism. 

Fu, B., Hsiao, B., Chen, G., Zhou J., Koyfman, I., Jamiolkowski D. D. and Dormier E., Structure and property studies of bioabsorbable poly(glycolide-co-lactide) fiber during processing and in vitro degradation. Polymer, 43,5527,2002. Fischer, E. W., Sterzel, H. J. and Wegner, G., Investigation of the structure of solution grown crystals of lactide copolymers by means of chemical reactions, Kolloid-Z. Z. Polym., 251,980. 1973. 

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