Detailed conformational knowledge of folded polymers and oligomers as well as supramolecular assemblies in protic solvents, including water, is of great current interest. 1 An intriguing question relates to whether the assembly exists in a disordered collapsed state or as a unique structure with a well-defined conformation and if a disordered state is present between the well-defined folded structure or aggregate and the unfolded or disassembled state. For assemblies in protic solvents, like chromonics in water, detailed information concerning conformational uniqueness is scarce. 2 Recently, Moore et al. showed that in the folding process for a series of oligo(m-phenylene ethynylene)s, formation of a disordered state precedes that of a unique helical conformation. 3

Regioregular polymers poly[4,4‘-bis(butylsulfanyl)-2,2‘-bithiophene] (P1) and poly[4,4‘-bis(octylsulfanyl)-2,2‘-bithiophene] (P2) were prepared from 4,4‘-bis(butylsulfanyl)- and 4,4‘-bis(octylsulfanyl)-2,2‘-bithiophene, by oxidative polymerization with FeCl3, and characterized by 1H and 13C NMR, FT-IR, and UV−vis spectroscopies, atomic force microscopy (AFM), electrical conductivity, and cyclic voltammetry measurements. They exhibit weight-average molecular weights of 8 and 70 kDa, respectively, and are both readily soluble in CHCl3, CH2Cl2, CS2, toluene, and THF. P1 has a lamellar structure, and P2 is a flexible and compact film that can be easily processed and manipulated. In the neutral state, they show UV−vis absorption maxima at about 470 nm in CHCl3 solution and exhibit marked solvatochromism and thermochromism. Furthermore, they can be cast from orange-red solution to form a violet film. The p-doping potentials have been determined, and the possibility of electrogenerating corresponding polymers has been checked. First comparative characterizations of the electrogenerated polymers have been carried out.

Aqueous dispersions of a regioregular polythiophene, bearing enantiomerically pure oligo-(ethylene oxide) side chains, are obtained by injecting small volumes of a THF solution of the polymer into water. The interplay of hydrophilic and hydrophobic interactions accounts for the unprecedented formation of hexagonal platelets, as well as other aggregates. Electron microscopy and selected area electron diffraction revealed that the platelets show diffraction patterns typical for single crystals. The relative amount of these highly ordered structures reaches 30% of all aggregates, in case of dispersions containing 10% (v/v) of THF in water. The effect of the organic solvent in controlling the formation of highly ordered assemblies is also investigated by means of UV-vis spectroscopy, where the occurrence of main chain organization gives rise to a distinct red-shifted absorption band. In the fluorescence spectra, the same situation accounts for quenching of the emission located at higher wavelengths with respect to the one in pure THF. The chiral information in the side chain is expressed at the supramolecular level in the highly ordered states, as revealed by CD spectroscopy. Notably, the intensity of the bisignated Cotton effect reaches its maximum at 10% (v/v) of THF, which coincides with the highest amount of single crystals in TEM. Thermochromic experiments show high thermal stability of the chiral assemblies in water.

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