Publication Date:
1995-07-07
Description:
Atomic force microscope images of zinc arachidate (ZnA2) Langmuir-Blodgett films show that three- and five-layer films are "hexatic," with long-range bond-orientational order and short-range positional correlations of three to five lattice repeats. The monolayer in contact with the substrate is disordered. Films of seven or more layers of ZnA2 are crystalline. A population of dislocations, most likely originating at the substrate, disrupts the positional but not the orientational order of the lattice, leading to hexatic layers intermediate between crystal and liquid. The influence of the substrate propagates farther into ZnA2 films than into cadmium arachidate films because the molecular cohesion is much weaker in ZnA2 than in cadmium arachidate, as evidenced by a less dense molecular packing.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Viswanathan, R -- Madsen, L L -- Zasadzinski, J A -- Schwartz, D K -- GM47334/GM/NIGMS NIH HHS/ -- HL51177/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1995 Jul 7;269(5220):51-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemical Engineering, University of California, Santa Barbara 93106, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7604278" target="_blank"〉PubMed〈/a〉
Keywords:
Chemistry, Physical
;
Crystallization
;
*Eicosanoic Acids
;
Fatty Acids, Unsaturated/*chemistry
;
Fourier Analysis
;
*Membranes, Artificial
;
Microscopy, Atomic Force
;
Physicochemical Phenomena
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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