Reversible Phase Transitions within Self-Assembled Fibrillar Networks of (R)-18-(n-Alkylamino)octadecan-7-ols in Their Carbon Tetrachloride Gels.
The CCl gel phases of a series of low-molecular-mass organogelators, (R)-18-(n-alkylamino)octadecan-7-ols (HSN-n, where n = 0-5,?18 is the alkyl chain length), appear to be unprecedented in that the fibrillar networks of some of the homologues undergo thermally reversible, gel-to-gel phase transitio...
| Publicado en: | Journal of the American Chemical Society Vol. 133; no. 38; pp. 15045 - 15055 |
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| Autores principales: | , , , , |
| Formato: | Artículo |
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American Chemical Society
9/28/2011
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=66650031&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 66650031 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 9/28/2011 vid: 133 iid: 38 pid: 997 pub: American Chemical Society artinfo: ui: 66650031 10.1021/ja204371b ppf: 15045 ppct: 10 formats: tig: atl: Reversible Phase Transitions within Self-Assembled Fibrillar Networks of (R)-18-(n-Alkylamino)octadecan-7-ols in Their Carbon Tetrachloride Gels. aug: au: Mallia, V. Ajay Butler, Paul D. Sarkar, Bijay Holman, K. Travis Weiss, Richard G. affil: Department of Chemistry, Georgetown University, Washington, D.C. 20057-1227, United States NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8562, United States su: Tetrachlorides Gelation Optical diffraction Phase transitions Cooling sug: subj: Tetrachlorides Gelation Optical diffraction Phase transitions Cooling ab: The CCl gel phases of a series of low-molecular-mass organogelators, (R)-18-(n-alkylamino)octadecan-7-ols (HSN-n, where n = 0-5,?18 is the alkyl chain length), appear to be unprecedented in that the fibrillar networks of some of the homologues undergo thermally reversible, gel-to-gel phase transitions, and some of those transitions are evident as opaque-transparent changes in the appearance of the samples. The gels have been examined at different concentrations and temperatures by a wide variety of spectroscopic, diffraction, thermal, and rheological techniques. Analyses of those data and data from the neat gelators have led to an understanding of the source of the gel-to-gel transitions. IR and SANS data implicate the expulsion (on heating the lower-temperature gel) or the inclusion (on cooling the higher-temperature gel) of molecules of CCl that are interspersed between fibers in bundles. However, the root cause of the transitions is a consequence of changes in the molecular packing of the HSN-n within the fibers. This study offers opportunities to design new gelators that are capable of behaving in multiple fashions without entering the sol/solution phase, and it identifies a heretofore unknown transformation of organogels. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2011 holdings: @attributes: islocal: N |
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