Gopal, Anesh ; Varghese, Reji ; Ajayaghosh, Ayyappanpillai (2012) Oligo(p-phenylene-ethynylene)-derived super-π-gelators with tunable emission and self-assembled polymorphic structures Chemistry - An Asian Journal, 7 (9). pp. 2061-2067. ISSN 1861-4728
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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/asia.20...
Related URL: http://dx.doi.org/10.1002/asia.201200410
Abstract
Linear π-conjugated oligomers are known to form organogels through noncovalent interactions. Herein, we report the effect of π-repeat units on the gelation and morphological properties of three different oligo(p-phenylene-ethynylene)s: OPE3, OPE5, and OPE7. All of these molecules form fluorescent gels in nonpolar solvents at low critical gel concentrations, thereby resulting in a blue gel for OPE3, a green gel for OPE5, and a greenish yellow gel for OPE7. The molecule–molecule and molecule–substrate interactions in these OPEs are strongly influenced by the conjugation length of the molecules. Silicon wafer suppresses substrate–molecule interactions whereas a mica surface facilitates such interactions. At lower concentrations, OPE3 formed vesicular assemblies and OPE5 gave entangled fibers, whereas OPE7 resulted in spiral assemblies on a mica surface. At higher concentrations, OPE3 and OPE5 resulted in super-bundles of fibers and flowerlike short-fiber agglomerates when different conditions were applied. The number of polymorphic structures increases on increasing the conjugation length, as seen in the case of OPE7 with n=5, which resulted in a variety of exotic structures, the formation of which could be controlled by varying the substrate, concentration, and humidity.
Item Type: | Article |
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Source: | Copyright of this article belongs to John Wiley and Sons. |
Keywords: | Conjugation; Fluorescence; Gels; Polymorphism; Self-Assembly |
ID Code: | 96147 |
Deposited On: | 05 Dec 2012 09:21 |
Last Modified: | 05 Dec 2012 09:21 |
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