Fluorescence probes for polymer free-volume

Abstract

Abstract

Novel Fluorophores for Single-Molecule Imaging

“…The lifetime of the fluorophore increases as the glass transition temperature (T g ) of the host polymer increases, suggesting that this fluorophore is sensitive to inherent differences in the polymer environments. Therefore, these dyes may be useful as single-molecule probes of local environmental viscosity, rigidity, or free volume in polymer films 29 . The photobleaching quantum efficiency (Φ B ) was determined for a bulk sample using an epifluorescence microscope as described above.…”

Spectroscopic investigation of cyanovinyl-diethylaniline dyes in solutions

“…For the dye /^(N,N-dimethylamino)-benzylidene malonitrile which is very similar to DCVA values of /* g =8.7 D and /* c =24 D were measured [ 8 ]. The spectral absorption and emission shifts with solvent polarity were utilized to monitor the dye location in polymers when they were used as microviscosity probes [ 9,10 ].…”

“…The dyes belong to a class of organic compounds known as molecular rotors [8][9][10][11] which have great importance as fluorescence probes of the flexibility of surrounding media [2,[8][9][10][11][12][13][14][15][16][17]. Some dicyanovinyl-alkylaniline dyes were ap- plied to determine static and dynamic changes of free volumes and torsional rigidities of polymers [9][10][11][12][13][14][15][16].…”

“…The electronic excitation of these dyes is accompanied by a large increase in the polarity due to changes in the charge distribution (internal charge transfer) [8][9][10][11][12][13][14][15][16][17][18][19][20]. The ground-state and excited-state dipole moments, // g and H e , of some dicyanovinyl-alkylaniline dyes were determined in refs.…”

Novel fluorophores for single-molecule imaging

“…18 Therefore, these dyes should be useful as a singlemolecule probe of local environmental viscosity, rigidity, or polymer-free volume. 19 The photobleaching quantum efficiency (Φ B ) was determined for a bulk sample using an epifluorescence microscope, as described elsewhere, 20 Table 1). …”