Oriented and Nanostructured Polycarbonate Substrates for the Orientation of Conjugated Molecular Materials and Gold Nanoparticles

Abstract

A simple method to prepare large areas of polycarbonate (PC) alignment layers with a high degree of polymer chain orientation, a periodic and oriented nanoscale pattern, and a controlled surface roughness is presented. The method involves three steps: (i) the preparation of a film of bisphenol A polycarbonate in its glassy state, (ii) the near-surface orientation of the polymer chains by rubbing, and (iii) exposure to vapors of acetone which acts as a plasticizer removing the microgrooves formed by rubbing and promotes solvent induced crystallization of PC. The resulting surface of the PC films is oriented and nanostructured, it consists of the periodic alternation of edge-on oriented crystalline lamellae and amorphous interlamellar zones with a total periodicity of ∼20 nm. The roughness of the oriented and nanostructured PC layers can be tuned by adjusting the exposure time to the solvent. The PC films exhibit a high orienting ability for various materials grown from the vapor phase, e.g., conjugated organic semiconductors and dyes (pentacene, phthalocyanine, bisazo dye) and metallic nanoparticles. Zinc phthalocyanine nanocrystallites and gold nanoparticles are observed to orient parallel to the crystalline lamellae of the PC substrate and not, as observed for polyimides, parallel to the polymer chain direction. It is proposed that the shallow surface nanocorrugation associated with the semicrystalline structure of the PC layers enforces the orientation of the ZnPc nanocrystallites and the gold nanoparticles.

Large Scale Alignment and Charge Transport Anisotropy of pBTTT Films Oriented by High Temperature Rubbing

“…Orientation of the films by mechanical rubbing follows the procedure described in an earlier work for the preparation of polycarbonate alignment layers. − It involves mainly two steps: (i) the preparation of a pBTTT film by the doctor blade method from a 4 wt % solution in ortho -dichlorobenzene ( o- DCB) on a clean glass substrate maintained at 180 °C and (ii) rubbing of the as-deposited films with a microfiber tissue. As shown in Figure , the rubbing machine is composed of a rotating cylinder (4 cm diameter) covered by a microfiber cloth.…”

Anisotropic highly-conductive films of poly(3-methylthiophene) from epitaxial electropolymerization on oriented poly(vinylidene fluoride)

“…[26][27][28][29] Signicant progress has been made in the epitaxial growth of organic semiconductive molecules on highly oriented polymer substrates. [30][31][32] For example, in our previous work, vapour phase epitaxial growth of perylo [1,12-b,c,d]thiophene (PTH) on highly oriented polyethylene (PE) gave large-area wellarranged lms of PTH with a unique crystal structure. 33 From this background we considered that introducing epitaxy into an electropolymerization process could provide an unusual method for preparing highly ordered thin lms of semiconductive materials.…”

Nanoprotective Layer-by-Layer Coatings with Epoxy Components for Enhancing Abrasion Resistance: Toward Robust Multimaterial Nanoscale Films

“…The mechanical abrasion tests of LbLfilms were carried out with a home-build apparatus described elesewhere. 33 In brief, a cylinder (4 cm diameter) covered with a microfiber cloth and rotating at a constant speed was pressed at ambient temperature with a constant pressure of 2 bar against a horizontally mounted LbL-film that was moved by a translation stage at constant speed opposite to the rotation direction of the cylinder. The brushing cycles were automated and electropneumatically controlled.…”