Morphological Transition from Nanosheet to Nanosphere in Ternary Comb Copolymers with Carbazole Rings

Abstract

The transition behavior of ternary comb copolymers containing carbazole rings from a monolayer on a water surface to a single particle layer has been investigated by surface pressurearea isotherms and atomic force microscopy. It has been found that these copolymers form a monolayer in the lowsurface-pressure region and a single particle layer in the highsurface-pressure region.Organized molecular films 1 fabricated using functional polymers with precisely controlled structures can be developed as candidates for biomimetic models 2 and molecular electronic devices, 3 which have attracted considerable interest in fundamental science, as well as for their potential applications. Generally, it is well known that crystalline polymers form hierarchical structures from lamellae on the nanometer scale to spherulite on the mesoscopic scale. 4 Crystals in these crystalline polymers are generally formed by the folding of the main chain, although there are two types of structural characteristics for side-chain crystalline ternary comb polymers. It is known that ternary comb polymers, which have long n-alkyl side chains with crystallization ability attached to an amorphous main chain, are packed into a layer structure along the c axis and subcell of the side chains in the ab plane.5 This "subcell" structure 6 of the side chain is formed as a two-dimensional lattice, and the "layer structure" along the c axis often reflects the long spacing between the main chains in the accumulated double-layer structures. With regard to the industrial application of these ternary comb polymers, poly(octadecyl)-based materials that utilize cocrystallization with another hydrocarbon to incorporate the material into the same crystalline lattice have found numerous applications such as pour-point depressants for lubricating oils or fuels, rheological modifiers, additives for petroleum products, and smart gels. 7On the other hand, in recent years, many researchers have attempted to utilize poly(N-vinylcarbazole) (poly-NVCz) as organic light-emitting diodes, organic transistors, and host compounds for organic electroluminescence 8 because it is well known that poly-NVCz exhibits properties identical to those of organic semiconductors.9 Further, it is expected that poly-NVCz can be used to realize a hologram memory material because of the high refractive index (>1.68) of its monomer. 10As mentioned above, it is essential to control the molecular orientation and arrangement at the monomolecular level in order to drive the functionality of these organic molecular devices in an efficient manner. However, in many cases, it is difficult to control the molecular arrangement and homopolymer packing because poly-NVCz itself easily forms an amorphous polymer. 11In a previous study, we investigated the control of solid-state structures and the formation of organized films for newly synthesized comb copolymers containing hydrogenated and fluorinated side chains.12 These comb polymers form a sidechain crystal in the bulk state via van der Waals interactions b...

Effect of Self-Assembled Monolayer Treated ZnO on the Photovoltaic Properties of Inverted Polymer Solar Cells

“…The increase in the contact angle possibly due to hydrophobic characteristic of carbazole and diphenylamine substituted benzoate. 33,34 From the contact angle data, we also conrm that SAMs based on benzoic acid derivatives are covered successfully on the ZnO layer.…”

Construction and Structural Estimation of Multilayered Organization of Polymer Nanosphere

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