Electrodeposited Poly(thieno[3,2‐b]thiophene) Films for the Templateless Formation of Porous Structures by Galvanostatic and Pulse Deposition

Abstract

The formation of porous nanostructures by using a templateless electropolymerization process with thieno[3,2‐b]thiophene as a monomer and two different deposition methods (galvanostatic and pulse potentiostatic deposition) has been studied. The wettability, roughness, and morphology of the surfaces are reported. The surfaces prepared by galvanostatic deposition show hydrophilic behavior (θw≈80°) that is highly dependent on the roughness. Nanoseeds were formed in the first instances followed by the formation of large microcapsules and hollow spheres. Indeed, as the deposition time and current density increase, the size and amount of structures also increase. By pulse deposition, the surfaces are hydrophobic (θw≈100°) and only show a roughness dependence if the mean surface roughness is >1.5 μm. The surfaces are formed from nanodomes and nanospheres, but they are less structured than that of surfaces produced by the galvanostatic method. The formation of these structures is directly related to the amount of gas released from trace water in situ during electropolymerization, which is highly dependent on the electrochemical method chosen. The formation of new seeds is highly favored by the galvanostatic method, whereas their growth is favored by the pulse deposition method. This is the first study on the use of galvanostatic and pulse deposition methods, with potential applications in surface chemistry. Thieno[3,2‐b]thiophene proved to be very versatile to form different structures with potential applications as water harvesting and separation membranes.

Designing Nanoporous Membranes through Templateless Electropolymerization of Thieno[3,4-b]thiophene Derivatives with High Water Content

“…As demonstrated by prior research, thieno­[3,4- b ]­thiophene monomers and associated analogues are excellent candidates to obtain nanotubular structures as well as hollow spheres via electrodeposition. − In this work, we demonstrate that with the judicious design of the thieno­[3,4- b ]­thiophene monomer structure, it is possible to obtain nanoporous membranes with the tunable size and surface hydrophobicity. Rigid substituents (e.g., perfluorinated chains, aromatic groups) were incorporated into thieno­[3,4- b ]­thiophene monomers (Scheme ) and their efficacy at electropolymerization was explored.…”

“…In these studies, tubular features form only if trace H 2 O is present in solution. Using this type of approach, vertically aligned nanotubes with high water adhesion have been developed using rigid monomers such as 3,4-phenylenedioxythiophene, naphthalenedioxythiophene, and thienothiophene derivatives. − …”

Influence of Polyfluorinated Side Chains and Soft‐Template Method on the Surface Morphologies and Hydrophobic Properties of Electrodeposited Films from Fluorene Bridged Dicarbazole Monomers

“…Indeed, their size and density on the surface electrode could be modulated by controlling electrochemical parameters (applied potential, concentration, time, etc.) in a clear voltammogram zone [20d,22] . Unfortunately, ITO electrodes suffer from degradation when exposed to hydrogen evolution from water discharge, which affects their chemical composition and conductivity [30] .…”

“…While much research has been performed to develop electropolymerizable monomers able to generate organic conducting polymers with different capabilities or physicochemical properties, [17,21] building out controlled electropolymerization processes that lead to films structured at the micro‐nanoscale can further expand the potential of these materials. In this regard, electrodeposition processes with the concomitant generation of gas microbubbles at the electrode surface by electrochemically discharge of a gas precursor as water are particularly intriguing [20a,d,22] . Indeed, the generated microbubbles work as soft template that makes that the polymer precipitate around them forming ordered pores or tubular structures.…”

Designing bioinspired coral-like structures using a templateless electropolymerization approach with a high water content

“…For templateless polymerization, its high polymerization capacity and rigidity make thieno [3,4-b]thiophene an excellent platform molecule. Previous monomers with substituents directly bonded on the 2-position have given excellent results [36][37][38].…”