Quest for a Rational Molecular Design of Alkyl–Distyrylbenzene Liquid by Substitution Pattern Modulation

Alkyl-π functional molecular liquids (FMLs) are of interest for fabricating soft electronic devices due to their fluidic nature and innate optoelectronic functions from the π-conjugated moiety. However, predictable development of alkyl-π FMLs with the desired liquid and optoelectronic properties is challenging. A series of alkyl–distyrylbenzene (DSB) liquids was studied in terms of the substituent position effect by attaching 2-octyldodecyl chains at (2,4-), (2,5-), (2,6-), and (3,5-). The effect of the alkyl chain length was investigated by attaching 2-hexyldecyl, 2-decyltetradecyl (C10C14), and 2-dodecylhexadecyl at the (2,5-) substituent position. The 2,5-C10C14 substituent pattern constructed a superior alkyl–DSB liquid with a lower viscosity, intrinsic optical properties, and high thermal- and photo-stabilities. The discovered 2,5-C10C14 was applied to dicyanostyrylbenzene and comparable liquid physical and optical superiorities were confirmed. This molecular design is useful for creating alkyl-π FMLs with the aforementioned advantages, which are applicable for deformable and flowable optoelectronic devices.