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Ordered organic thin films self-assembled from the vapor phaseOrganic films self-assembled from a liquid phase, as in Langmuir-Blodgett or adsorption from solution, have received much attention in the past decade as techniques to achieve highly oriented-ordered polymeric thin films. Many organic compounds including some of the same fatty acids have been vapor deposited as well. However, organic pigments and dyes comprise a major class of important materials which have very low solubilities yet excellent thermal stabilities, making them ideally suited for film deposition from the vapor phase. Surprisingly, such molecular systems exhibit a significant propensity to self order, a high sensitivity to deposition parameters, and a range of microstructural forms that cannot be duplicated by the less energetic mechanisms associated with solution adsorption processes. Molecular solids such as heterocyclic polynuclear aromatics are excellent candidates for film formation by vacuum deposition means. Over the past decade, our work and that of others investigating a wide variety of perylene and phthalocyanine derivatives identified five deposition parameters that can significantly affect film morphology, physical microstructure, and type and extent of ordering developed in vacuum and vapor transport grown films. These parameters are substrate temperature, deposition rate, substrate chemistry and epitaxy, ambient gas convective flows, and post deposition annealing. Examples of how each of these conditions manifest themselves in the film structure and ordering, most frequently revealed by scanning electron microscopy, reflection absorption infrared spectroscopy (RAIR), and grazing incidence x-ray diffraction (GIX), are presented.
Document ID
19940019866
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Debe, M. K.
(Minnesota Mining and Mfg. Co. Saint Paul, MN, United States)
Date Acquired
September 6, 2013
Publication Date
December 1, 1993
Publication Information
Publication: NASA. Marshall Space Flight Center, Microgravity Studies of Organic and Polymeric Materials
Subject Category
Nonmetallic Materials
Accession Number
94N24339
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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