Nanoscale Organization of Conjugated Rods in Rod-Coil Molecules

Abstract

Conjugated rod molecules bearing flexible coil polymer moieties on both ends self‐organize into 1D or 2D structures, and eventually into a 3D tetragonal superlattice (see Figure), depending on the number of monomeric units in the coils. The 3D ordered rods exhibit a highly extended fluorescence lifetime over the 1D or 2D arrays, making synthetic control of the rod‐to‐coil volume fraction a viable strategy to regulate photophysical properties.

Supramolecular honeycomb and columnar assemblies formed by self-assembly of coil-rod-coil molecules with a conjugated rod segment

“…29,30 It should be pointed out that in contrast with molecules 7 and 8, SAXS studies by Cho and Lee showed hexagonal columnar and body-centered tetragonal nanostructures for 9 and 10 in the crystalline phase respectively, although, 9 ( f coil =0.68) and 10 ( f coil =0.75) with a linear PPO coil segment actually have identical coil volume fractions of corresponding 7 and 8. 21 This interesting result can be explained the different density of the coil/rod interface, and is dependent upon coil cross section. For molecules 9 and 10, the larger cross sectional area of the coil domains leads to 2-D hexagonal columnar and 3-D body-centered tetragonal nanostructures in the crystalline phase.…”

“…Compounds 1-4 and phosphonium salt was synthesized according to the procedure described eleswhere. 21,22 Techniques. 1 H NMR spectra were recorded from CDCl 3 solutions on a Bruker AM 300 spectrometer.…”

“…4,8,20 Lee and coworkers have reported synthesis and electro-optical studies of self-organizing coil-rod-coil triblock molecules consisting of three biphenyls connected through vinylene linkages as a conjugated rod segment and poly(propylene oxide) (PPO) as the coil segment (molecules 9 and 10 see Scheme I). 21 The results of structural analysis indicate that these molecules are self-organized into 1-D lamellar, 2-D hexagonal, and 3-D tetragonal supramolecular structures with increasing coil volume fraction in the crystalline state.…”

Transport and Electro‐Optical Properties in Polymeric Self‐Assembled Systems

“…The micelles have diameters of approximately 8-10 nm and are composed of an conjugated block surrounded by a poly(ethylene glycol) corona. An even more rigid conjugated block was used in triblock copolymers where the central block consists of three biphenyls connected using vinylene groups and the end blocks are poly(propylene oxide) [349]. A brilliant blue emission was observed with a fluorescence maximum at 479 nm.…”

“…3. 20 An example of ABA-type coil-rod-coil triblock copolymer with a conjugated central block and the structures obtained [349].…”