@article { ISI:000265030500015,
	title = {Supramolecular ring banded prototype liquid crystalline oligo(phenylenevinylene)},
	journal = {Journal of Physical Chemistry B},
	volume = {113},
	number = {15},
	year = {2009},
	month = {APR},
	pages = {5083-5091},
	publisher = {AMER CHEMICAL SOC},
	address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
	abstract = {<p>We report a new ring banded supramolecular structure in thermotropic liquid crystalline oligo(phenylenevinylene) (OPV) via a melt crystallization process. A series of structurally different OPV molecules were synthesized using tricyclodecanemethanol (TCD) as a bulky pendant unit to trace ring banded morphology. Among all, an OPV molecule with rigid bis-TCD units in the central core and flexible dodecyl chains at the outer phenyl rings (BTCD-BDD-OPV) was found to show ring banded morphologies, which is a first of its kind in T-conjugated materials. BTCD-BDD-OPV experiences strong aromatic pi-pi interactions in both film and liquid crystalline (LC) frozen stage. The pi-induced aggregation leads to lamellar self-assembly of OPV-mesogens that subsequently undergo helical crystal growth, thereby producing dark and bright ring banded patterns. Variable temperature X-ray diffraction analysis revealed the existence of three peaks at 27.07, 13.97, and 8.90 angstrom corresponding to 001, 002, and 003 fundamental layers, respectively, thus confirming the lamellar self-assembly of OPV-mesogens. Electron microscopic (SEM and TEM) analysis of the LC frozen sample showed images confirming helical microcrystalline assembly and providing direct evidence for the self-organization mechanism. Detailed photophysical experiments such as excitation, emission, and timeresolved fluorescence decay studies indicated that BTCD-BDD-OPV has very strong pi-pi interaction in both film and LC frozen stage, which was found to be main driving force for the formation of supra-ring structure. Upon illumination with light, the OPV chromophores in the LC phase were excited and the color of the samples turned into luminescent green ring bands.</p>},
	issn = {1520-6106},
	doi = {10.1021/jp809994t},
	author = {Amrutha, S. R. and Jayakannan, M.}
}
