Nanofold‐decorated surfaces from the electrodeposition of di‐alkyl‐cyclopentadithiophenes

Abstract

This work describes the synthesis and subsequent electrodeposition of 4H-cyclopenta[2,1-b:3,4-b′]dithiophene (cyclopentadithiophene) monomers di-substituted with alkyl chains. Each monomer was electropolymerized in solution to observe their capacity at creating well-structured, rough surfaces. The length of the alkyl chain substituent has a significant influence on the overall surface morphology and wetting behavior after electropolymerization. In the case of nonsubstituted cyclopentadithiophene monomers or those with short alkyl (methyl and ethyl) substituents, the polymerization proceeds readily, forming rough surfaces that follow the Wenzel regime of wetting. In these cases, the surfaces were decorated with globular agglomerates and woven mat features. The measured surface roughness decreases with alkyl chain length as steric hindrance caused by the alkyl substituents limits electropolymerization. As the alkyl chain substituent increases to propyl chain length and beyond, the increase in steric hindrance is so significant that the surface morphology formed during electrodeposition is primarily due to π-stacking interactions between very short oligomers formed in solution. With propyl and butyl substituents, nanofold morphology is observed, leading to surfaces with much higher contact angles with water (~132°) that follow the Cassie-Baxter regime of wetting. This type of surface morphology has only been demonstrated one other time and with the use of fluorinated constituents. This work exposes a mild, fluorine-free synthetic route to creating nanofold-decorated surfaces.

Linear and Nonlinear Optical Properties of Quadrupolar Bithiophenes and Cyclopentadithiophenes as Fluorescent Oxygen Photosensitizers

“…Cyclopentadithiophene Derivatives. The known cyclopentadithiophene 8 [32] was di-iodinated at the C2 and C6 positions using N-iodosuccinimide, affording 9 in a 89% yield. Double Sonogashira coupling between 9 and the terminal alkyne 10 [33] afforded the push-push derivative 2a in 45% yield.…”

“…The commercial reagents and (pre-/co-)catalysts were used as received. N,N-diphenyl-4-[2-(trimethylsilyl)ethynyl]-aniline (5) [29], 5,5diethynyl-2,2 -bithiophene (6b) [30], 1-bromo-4-[(trifluoromethyl)sulfonyl]benzene (7) [32], N,N-diphenyl-4-ethynylaniline (10) [33] and 1-[(trifluoromethyl)sulfonyl]-4-[2-(trimethylsilyl)ethynyl]benzene (11) [25] were synthesized as described in the literature. After stirring at 85 • C for 36 h, the solvents were evaporated under reduced pressure and the residue was purified by column chromatography (heptane/CH 2 Cl 2 90:10 then a column chromatography eluent (heptane) to give 166.4 mg (89%) of 9 as a pale-yellow solid (that needs to be stored in the cold).…”

Bioinspired surfaces with strong water adhesion from electrodeposited poly(thieno[3,4-b]thiophene) with various branched alkyl chains

“…The electropolymerization process has been used in the literature to rapidly form on working electrode substrates conducting polymer films with various surface energy and surface structures [18][19][20][21][22][23][24][25].…”

“…For the electropolymerization core, thieno [3,4-b]thiophene combines both exceptional polymerization capacity leading to polymers with unique opto-electronic properties, and a relatively easiness to introduce various substituents [26,27]. To adapt both surface hydrophobicity and water adhesion, perfluorinated or linear alkyl chains can be replaced by branched alkyl chains or aromatics groups [18][19][20][21][22].…”