Fluorinated Oleophilic Electrochromic Copolymer Based on 3‐(N‐Trifluoroacetamido)thiophene and 3,4‐Ethylenedioxythiophene (EDOT)

Abstract

A new fluorine-containing monomer 3-(Ntrifluoroacetamido)thiophene (F-TH) was synthesized and characterized for the first time. Its molecular structure was determined by a single-crystal X-ray study. F-TH functions as a building block in electropolymerization with 3,4-ethylenedioxythiophene (EDOT) gives a novel conjugated copolymer P(F-TH:EDOT) subsequently. Compared with the parent homopolymer poly(3,4ethylenedioxythiophene) (PEDOT) film, sponge-like nanoporous P(F-TH:EDOT) film has a slightly larger band gap with a reduced hydrophilic and increased oleophilic surface. Spectroelectrochemical analysis results reveal that P(F-TH:EDOT) exhibits excellent electrochromic performances with higher optical contrast (55%) and much shorter coloring time (0.70 s) than that of PEDOT (43%, 1.54 s). The coloration efficiency value of P(F-TH:EDOT) achieves up to 167.9 cm 2 /C, 55% higher than that of PEDOT (108.1 cm 2 /C). These improved electrochromic properties of P(F-TH:EDOT) are probably related with the enhanced wettability to electrolyte solution.Electrochromic conjugated polymers (ECPs), which can effectively adjust the transmitted and reflected light based on their reversible redox states under small external voltages, have been extensively investigated owing to their potential applications on smart windows and mirrors, displays, thermal control, camouflage and sensors. [1][2][3][4][5][6][7][8] As the most established ECPs, thiophene-based polymers have been extensively investigated due to their significant optical changes between redox states, outstanding coloration efficiency and facile switching performances. 9-12 To date, a lot of monomers from the family of thiophenes have been developed as building blocks, and based on them, various ECPs with different properties have been synthesized, [13][14][15][16][17][18] but the

Low-Cost Fabrication of High-Performance Fluorinated Polythiophene-Based Vis–NIR Electrochromic Devices toward Deformable Display and Camouflage

“…Among the various strategies for designing high-performance electrochromic conjugated polymers, fluorine substitution has been frequently investigated to tune molecular interactions as well as electronic, morphological, and photoelectronic properties. − To enhance the optoelectronic and mechanical properties of polythiophenes for flexible ECDs, we introduce the substitution of the fluorophenyl group on the C2 positions of the polythiophene backbone without destroying the conjugated chain structure and increasing the material cost much (Figure a). The strategy involves one-step synthesizing the 3-(4-fluorophenyl)­thiophene (FPT) precursor, followed by its simple electropolymerization to achieve the poly­(3-(4-fluorophenyl)­thiophene) (PFPT) film.…”

“…80% at 1600 nm), fast response time (0.93 s), high coloration efficiency (up to 752 cm 2 C −1 ), outstanding stability against cycling (<3% reduction after 5,000 cycles), and excellent optical memory effect, superior to those found in previous reports. 30,31 Based on these findings, the as-fabricated FECDs by direct electropolymerization patterning show robust mechanical stability (<5% decay in optical contrast after 5,000 bending cycles with a bending radius of 1 cm) under low driving voltages. We further demonstrate the applications of such patterned electrochromic devices toward deformable displays, color-changing tattoos, and infrared camouflage with stable color-switching and robust mechanical properties.…”

“…Among various electrochromic materials, conjugated polymers like polythiophenes (PThs) show great promise as ideal candidates because of their superior electrochromic performance, facile synthesis, lower redox potentials, and compatibility with scalable processing. − Fluorine-containing substitution on the backbone of PTh can potentially help improve charge transport to improve electrochromic performances due to several prominent features of the fluorine (F) atom: (1) the van der Waals radius of the fluorine atom is only slightly larger than that of the hydrogen atom and thus can effectively minimize steric hindrance and enable better planarity of the polymer backbones for efficient charge transportation; (2) the intramolecular and intermolecular interactions can be enhanced in fluorinated molecules due to dynamic noncovalent interactions such as hydrogen bonding of H···F and C–F···π F , which can promote crystallinity and charge transport property; and (3) fluorination can reduce the exciton binding energy and increase the lifetime of the charge carrier by promoting the relative dielectric constants of the resulting materials . However, despite these potential advantages, such fluorinated polythiophenes have been rarely reported for polymeric electrochromics previously. − …”

Electrochromic properties of pyrene conductive polymers modified by chemical polymerization

“…In order to more directly explore the switching response time and coloring efficiency of the synthesized polymers, we compared them with the existing literature on thiophene polymers, triphenylamine polymers, EDOT polymers and pyrene polymers. [51][52][53][54] Through comparison, the ve polymers had shorter switching response time and higher coloring efficiency. In summary, all the synthesized polymers have stable electrochromic properties and high coloring efficiency, and they are excellent electrochromic materials.…”

Electropolymerization of Thiophene‐Based Monomers with Different Spatial Structures: The Impact of Monomer Structure on Electrochromic Properties

“…[1][2][3][4] Due to the electrochromic devices (ECD) generally have simple device DOI: 10.1002/macp.202100341 structures and low applied potential, they have been widely used in displays, smart windows, military camouflage, car antiglare rearview mirrors, etc. [5][6][7] Traditional organic EC materials are mainly prepared by chemical synthesis, but which is not only complicated to purify, difficult to recycle, and pollutes the environment. [8][9][10] As a new polymerization method, due to its simple polymerization conditions, high degree of polymerization, and good film-forming properties, a large number of conductive polymers (CPs) have been currently synthesized by electropolymerization.…”