Fluorescent doughnut-like assembling of wire-type dendrimers depending on their generation numbers and degrees of polymerization

Citation
S. Masuo et al., Fluorescent doughnut-like assembling of wire-type dendrimers depending on their generation numbers and degrees of polymerization, J PHYS CH B, 105(15), 2001, pp. 2885-2889
Citations number
16
Language
INGLESE
art.tipo
Letter
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHYSICAL CHEMISTRY B
ISSN journal
1520-6106 → ACNP
Volume
105
Issue
15
Year of publication
2001
Pages
2885 - 2889
Database
ISI
SICI code
1520-6106(20010419)105:15<2885:FDAOWD>2.0.ZU;2-J
Abstract
The self-assembled structures by evaporation of tetrahydrofuran (THF) solut ion of wire-type dendrimers have been studied by some spectroscopic and mic roscopic techniques. Doughnut-like structures were obtained for some dendri mers with generation number of 2 and about 28 nm length by depositions thei r THF solutions on a quartz substrate, while yam-like and particle-like str uctures were obtained for other dendrimers. The size of the doughnut struct ure Varied from I to 8 mum in diameter and between 30 and 150 nm in height. Confocal fluorescence microscopy, atomic force microscopy (AFM), and near- field scanning optical microscopy (NSOM) were applied to elucidate assemble d structures and electronic properties in addition to conventional fluoresc ence spectroscopy. Polarization and local fluorescence measurements at some parts of doughnuts and particles were demonstrated, however, no correlatio n between molecular orientation/intermolecular interaction and doughnut str uctures was found. The doughnut formation mechanism is considered on the ba sis of evaporation processes observed from in situ experiments.