The Crystalline Morphology of Poly(N-vinylcarbazole)

Abstract

will be approximately 0.2 in systems where the carbonyl is isolated from similar groups along the chain and where the molecular mobility is high. In solid polymers, the quantum yield will be reduced to very low values at temperatures below the glass-transition temperature of the polymer because of the restriction in molecular mobility. We suggest that the scission mechanism in such copolymers involves the breaking of either a-8 or i3-7 carbon-carbon bonds through an intermediate transition state consisting of either a sixor a sevenmembered ring through a y-or 5-hydrogen atom. We further conclude that transfer of excitation energy along a polymer chain will be possible in systems where similar chromophores are located in adjacent positions along the backbone. When such is the case, one may expect to get substantial changes in the quantum yields for the observed photochemical processes.

Poly(α-vinyl-ω-alkyloligothiophene) Side-Chain Polymers. Synthesis, Fluorescence, and Morphology

“…The structural regularity of the polymers was demonstrated by their proton and carbon-13 NMR spectra. The 1 H and 13 C NMR characteristics of the polymers are given in Table 1. The assignments were based on routine monodimensional (DEPT) and bidimensional spectra (COSY, ghsqc).…”

“…1 H NMR (CDCl3): δ ppm 0.9-1.8 (m, 11H), 2.8 (t, 2H), 5.12 (d, J ) 10 Hz, 1H), 5.52 (d, J ) 17 Hz, 1H), 6.65-6.85 (m, 3H), 6.94-7.6 (m, 4H). 13 5-Hexyl-2,2′;5′,2′′;5′′,2′′′-quaterthiophene-5′′′-carbaldehyde, 21. Pd2(dba)3 (6.9 mg, 0.0067 mmol) and AsPh3 (16.3 mg, 0.053 mmol) were dissolved in dry toluene (10 mL) under a nitrogen atmosphere.…”

“…One approach is to interconnect thiophene oligomers by means of a polyvinyl chain to generate polymers with a structure similar to that of poly(N-vinylcarbazole), a well-known electroactive polymer whose morphology can be oriented by the choice of appropriate experimental conditions. 13 More recently, new families of polyvinyl polymers with bulky pendant groups have been described, whose supramolecular self-assembly properties are tuned via the appropriate choice of the side groups. [14][15][16] It is likely that, when interconnected by a polyvinyl chain, thiophene oligomers interact with modalities different from those typical of the free oligomers, owing to the steric constraints imposed by the repetition period of the structure, thus leading to the expression of new and attractive properties.…”

Manipulating Supramolecular Self-Assembly via Tailoring Pendant Group Size of Linear Vinyl Polymers

“…It has been known for years that atactic vinyl polymers (random sequences of d - and l -configurations along polymer backbones) with large side groups possess a second scattering halo in the low 2θ angle region (below 10°) in wide-angle X-ray diffraction (WAXD) experiments. Some polymers, such as poly( N -vinylcarbazole), , poly[dicyclohexyl vinylterephthalate], and poly[di(4-heptyl) vinylterephthalate] (PDHVT), exhibit sharp diffractions at low 2θ's due to the existence of ordered structures. For example, the side group of PDHVT contains a pair of 4-heptyl groups at the 2- and 5-positions of the substituted phenyl group linked via ester bonds that are laterally attached to the backbone through a single carbon−carbon bond.…”

Poly(9‐vinylcarbazole)/silver composite nanotubes and networks formed at the air–water interface

“…[8][9][10] PVK is a photoconductive semiconductor polymer that possesses a high glass-transition temperature and good processability. Because of its specific electric and optical properties and wide applications in microelectronics, the structure and properties, including the crystalline morphology, 11 conformation, 12 and emission properties, [13][14][15][16] of bulk PVK have been studied extensively. Recently, inorganic nanoparticle/PVK nanocomposites have aroused much attention because of their unique photoconductive and photorefractive properties, which show important applications in high-density optical storage, optical amplification, and dynamic image processing.…”