Interfacial crystallization

The instability of these chiral monolayers may be a reflection of the relative stabilities of their bulk crystalline forms. When deposited on a clean water surface at 25°C, neither the racemic nor enantiomeric crystals of the tryptophan, tyrosine, or alanine methyl ester surfactants generate a detectable surface pressure, indicating that the most energetically favorable situation for the interfacial/crystal system is one in which the internal energy of the bulk crystal is lower than that of the film at the air-water interface. Only the racemic form of JV-stearoylserine methyl ester has a detectable equilibrium spreading pressure (2.6 0.3dyncm 1). Conversely, neither of its enantiomeric forms will spread spontaneously from the crystal at this temperature. 

M. L. Minus, H. G. Chae, S. Kumar, Interfacial crystallization in gel-spun poly(vinyl alchohol) single-wall carbon nanotubes composite fibers, Macromol. Chem. Phys, vol. 210, pp. 1799-1808, 2009. 

At temperatures above 25°C, the presence of emulsifier results in only a slight reduction in interfacial tension compared to a pure oii-water interface (7 25 mN/m). When the temperature is decreased further, a significant drop in interfacial tension (7) is registered due to interfacial crystallization followed by crystallization of emulsifier in the bulk oil phase below 15°C. The increase in 7 observed at temperatures below 10°C is artificial being caused by a viscosity increase due to the crystal network which has formed. 

Interfacial crystal angle The angle between the two normals to the crystal planes or crystal faces. 

Heterogeneous epitaxy is a specific interfacial crystallization between different polymer pairs due to lattice matching. Heterogeneous epitaxy at interfaces may be an active way to improve the mechanical properties of polymer blends, especially for incompatible systems. The epitaxial growth of HDPE and LLDPE on the... 

Lin, C.W., Ding, S.Y. and Hwang, Y.W. 2001. Interfacial crystallization of isotactic polypropylene molded against the copper surface with various surface roughnesses prepared hy an electrochemical process. J. Mater. Sci. 36 4943 948. 

MJ FoUces. Interfacial crystallization of polypropylene in composites. In J Karger-Kocsis, ed. Polypropylene Structure, Blends and Composites. 1st ed. London Chapman and Hall, 1995, 3, p 340. 

Folkes, M.J. (1995) Interfacial crystallization of pol) ropylene in composites, in Polypropylene Structure, Blends and Composites, Vol. 3, Chap. 10, (ed. J. Karger-Kocsis), Chapman Hall, London, pp. 340-370... 

Abstract Detailed investigations of interfacial crystallization procedures are important to understand the basic principles of biomineralization processes. These interfacial phenomena can also be used to form new types of biomimetic composite materials. In a series of experiments we studied the influence of Langmuir-monolayers on the formation of ultra-thin calcium carbonate Aims. We systematically compared experiments performed at the water surface wi results obtained at the water/oil interface. 

Fig. 37.7 (a) Chemical structures of acetaminophen and p-amidophenol-modified calix[4]arene (b) Snapshot of the interfacial crystallization of acetaminophen at the air-water interface (Reproduced with permission from Ref [34], Copyright 2011, American Chemical Society)... 

Langmuir monolayers of calixarenes have also been studied for their ability to bind small organic molecules. Recently, we reported on the ability of Langmuir monolayers of an amphiphilic p-amidophenolcalix[4]arene derivative to interact with acetaminophen (APAP) [34, 49], an active pharmaceutical ingredient (API) widely used as analgesic and antipyretic, at the air-water interface. Interestingly, these calixarene-based surfaces act as templates for the interfacial crystallization of the pharmaceutical (Fig. 37.7) [34]. The similarity between the polar functions of the amphiphUe and the stmcture of APAP were shown to favor the molecular recognition event. 

Pieranski, Pawel, 1980, Two-Dimensional Interfacial Crystals, Phys. Rev. Lett., 45 569. 

Ning N, Fu S, Zhang W, Chen F, Wang K, Deng H, et al. Realizing the enhancement of interfacial interaction in semicrystalline polymer/filler composites via interfacial crystallization. Prog Polym Sci 2012 37 1425-55. 

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