Small molecule self‐assembly in polymer matrices

Abstract

Using small molecules in polymer matrices is common in applications such as (i) plasticizing polymers to modify the glass transition and mechanical properties and (ii) dispersion of photoactive or electroactive small molecules in polymer matrices in organic-electronic devices Aggregation of these small molecules and phase separation leading to crystallization often cannot be morphologically controlled. If these are designed with self-assembling codes such as hydrogen bonding or aromatic interactions, their phase separation behavior would be distinctly different. This review summarizes the studies on morphologies in such situations, such as (i) sub-surface assembly in polymer matrices, (ii) controlled polymerizationinduced phase separation to create polymer blends, (iii) using the polymer to direct the assembly of small molecules in liquid crystalline devices, (iv) functionalizing a polymer with selfassembling small molecules to cause organo-gelation which the polymer itself would not by itself, and (v) using such systems as templates to create porous polymer structures. Organic-inorganic hybrids using polymers as templates for nanostructures and imprinted porous membranes is an emerging area. Since self-assembly is one of the dominating area of research with respect to both small molecules, polymers as well as the combination of the two, this review summarizes the studies on the aforementioned topics.

Rapid and high-resolution patterning of microstructure and composition in organic semiconductors using ‘molecular gates’

“…10b and Supplementary Table 1 , reducing writing speed (i.e., increasing the effective diffusion time) by a factor of 600 leads only to a minor factor of 1.6 average increase in pattern dimensions. This indicates that the parasitic in-plane diffusion component is relatively small, as can be expected from an Arrhenius-type exponential dependence of diffusion coefficient on temperature 36 , with the latter decreasing sharply outside the laser-illuminated area. On the contrary, increasing laser power by a factor of 2 leads to a factor of 2.2 average increase in pattern dimensions, indicating that the laser-heating-induced temperature rise is the primary parameter governing pattern dimensions.…”

“…The stimulus, whether heat- or solvent-vapour-based, is employed to impart molecular mobility to the compounds comprising the donor layer by melting or swelling. The resulting rate of diffusion of said compounds into the donor layer scales exponentially with temperature and is governed by additional parameters such as glass transition of the target semiconductor film, molar mass of the functional compounds and thickness of the molecular gate 36 . As laser light is the most versatile choice of stimulus, the following sections will present local patterning of various feature types by laser-induced ‘gated’ diffusion.…”

Self-assembly of quaternary ammonium gemini surfactants in cyclohexane upon reinforcement by simple counterions

“…This is a spontaneous and reversible molecular associating process, during which intermolecular non-covalent forces such as aromatic (p/p), hydrogen bonds, van der Waals, electrostatic and hydrophobic/solvophobic interactions are included. 1 At present, research on molecular self-assembly is very active and fruitful in biological, [2][3][4][5][6] materials, [7][8][9][10] and drug delivery [11][12][13] elds, which contributes to the development of these areas both in terms of scientic knowledge and practical application.…”

Phenacyl Phenothiazinium Salt as a New Broad‐Wavelength‐Absorbing Photoinitiator for Cationic and Free Radical Polymerizations

“…[10] Depending on the structure of the chromophore group containing heteroatom, the absorption of the salt can be shifted to longer wavelengths. Previously, phenacyl salts with sulphonium, [11] aniline, [12] pyridine, [13] carbazole, [14] and thioxathone [15] groups were synthesized and successfully used in cationic, free radical and step-growth [16] polymerizations. It was also shown that their charge transfer complexes further extend their absorption characteristics to longer wavelengths.…”

“…[8] As an efficient chromophore, phenacyl group has been incorporated into various heteroatom containing molecules to enhance spectral sensitivity. [11][12][13][14][15] We incorporated phenacyl group to photosensitive phenothiazine as an additional chromophore. P-PTh was prepared by direct phenacylation process of N-ethyl-phenothizine (E-PTh) in one step, one pot according to generally applied method.…”