skip to main content


Title: Spatially Directed Functionalization by Co-electropolymerization of Two 3,4-ethylenedioxythiophene Derivatives on Microelectrodes within an Array

Electrodeposited conductive copolymer films with predictable relative properties (quantities of functional groups for further modification and capacitance) are of interest in sensors, organic electronic materials and energy applications. Potentiodynamic copolymerization of films in aqueous solutions of two different thiophene derivatives, (2,3-dihydrothieno[3,4-b]dioxin-2-yl)methanol (1) and 4-((2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)-methoxy)-4-oxobutanoic acid (2), containing 0.02 M total monomer (0, 25, 34, 50, 66, 75, 100 mol%2), 0.05 M sodium dodecyl sulfate, and 0.1 M LiClO4, on gold microelectrodes in an array was investigated. Decreasing monomer deposited (m)from 0 to 100 mol%2is attributed to a decreasing pH that inhibits electropolymerization. Molar ratios of1and2in the films, determined by micro-attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, tracks closely with the ratio in the deposition solutions. Capacitances measured from cyclic voltammetry in aqueous buffer and electron transfer of ferrocyanide at the films are unaffected by copolymer composition, except for the 100 mol%2case. Ratios of reverse-to-forward faradaic peak currents suggest that films with high content of1expand in the anodic form and contract in the cathodic form and vice versa for films with high content of2, where anions and cations dominate counterion transport from solution, respectively.

 
more » « less
Award ID(s):
1808286
NSF-PAR ID:
10361213
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
The Electrochemical Society
Date Published:
Journal Name:
Journal of The Electrochemical Society
Volume:
167
Issue:
16
ISSN:
0013-4651
Page Range / eLocation ID:
Article No. 166511
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    Efficient doping of polymer semiconductors is required for high conductivity and efficient thermoelectric performance. Lewis acids, e.g., B(C6F5)3, have been widely employed as dopants, but the mechanism is not fully understood. 1:1 “Wheland type” or zwitterionic complexes of B(C6F5)3are created with small conjugated molecules 3,6‐bis(5‐(7‐(5‐methylthiophen‐2‐yl)‐2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐5‐yl)thiophen‐2‐yl)‐2,5‐dioctyl‐2,5‐dihydropyrrolo[3,4‐c]pyrrole‐1,4‐dione [oligo_DPP(EDOT)2] and 3,6‐bis(5''‐methyl‐[2,2':5',2''‐terthiophen]‐5‐yl)‐2,5‐dioctyl‐2,5‐dihydropyrrolo[3,4‐c]pyrrole‐1,4‐dione [oligo_DPP(Th)2]. Using a wide variety of experimental and computational approaches, the doping ability of these Wheland Complexes with B(C6F5)3are characterized for five novel diketopyrrolopyrrole‐ethylenedioxythiophene (DPP‐EDOT)‐based conjugated polymers. The electrical properties are a strong function of the specific conjugated molecule constituting the adduct, rather than acidic protons generated via hydrolysis of B(C6F5)3, serving as the oxidant. It is highly probable that certain repeat units/segments form adduct structures inp‐type conjugated polymers which act as intermediates for conjugated polymer doping. Electronic and optical properties are consistent with the increase in hole‐donating ability of polymers with their cumulative donor strengths. The doped film of polymer (DPP(EDOT)2‐(EDOT)2) exhibits exceptionally good thermal and air‐storage stability. The highest conductivities, ≈300 and ≈200 S cm−1, are achieved for DPP(EDOT)2‐(EDOT)2doped with B(C6F5)3and its Wheland complexes.

     
    more » « less
  2. Abstract

    Reaction of (P)AuOTf [P=P(t‐Bu)2o‐biphenyl] with indenyl‐ or 3‐methylindenyl lithium led to isolation of gold η1‐indenyl complexes (P)Au(η1‐inden‐1‐yl) (1 a) and (P)Au(η1‐3‐methylinden‐1‐yl) (1 b), respectively, in >65 % yield. Whereas complex1 bis static, complex1 aundergoes facile, degenerate 1,3‐migration of gold about the indenyl ligand (ΔG153K=9.1±1.1 kcal/mol). Treatment of complexes1 aand1 bwith (P)AuNTf2led to formation of the corresponding cationic bis(gold) indenyl complexestrans‐[(P)Au]211‐inden‐1,3‐yl) (2 a) andtrans‐[(P)Au]212‐3‐methylinden‐1‐yl) (2 b), respectively, which were characterized spectroscopically and modeled computationally. Despite the absence of aurophilic stabilization in complexes2 aand2 b, the binding affinity of mono(gold) complex1 atoward exogenous (P)Au+exceed that of free indene by ~350‐fold and similarly the binding affinity of1 btoward exogenous (P)Au+exceed that of 3‐methylindene by ~50‐fold. The energy barrier for protodeauration of bis(gold) indenyl complex2 awith HOAc was ≥8 kcal/mol higher than for protodeauration of mono(gold) complex1 a.

     
    more » « less
  3. Abstract

    A non‐volatile conjugated polymer‐based electrochemical memristor (cPECM), derived from sodium 4‐[(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methoxy]butane‐2‐sulfonate (S‐EDOT), is fabricated through roll‐to‐roll printing and exhibited neuromorphic properties. The 3‐terminal device employed a “read” channel where conductivity of the water‐soluble, self‐doped S‐PEDOT is equated to synaptic weight and was electrically decoupled from the programming electrode. For the model system, a +2500 mV programming pulse of 100 ms duration resulted in a 0.136 μS resolution in conductivity change, giving over 1000 distinct conductivity states for one cycle. The minimum programming power requirements of the cPECM was 0.31 pJ mm−2and with advanced printing techniques, a 0.1 fJ requirement for a 20 μm device is achievable. The mathematical operations of addition, subtraction, multiplication, and division are demonstrated with a single cPECM, as well as the logic gates AND, OR, NAND, and NOR. This demonstration of a printed cPECM is the first step toward the implementation of a mass produced electrochemical memristor that combines information storage and processing and may allow for the realization of printable artificial neural networks.

     
    more » « less
  4. Abstract

    This study introduces a benzodithiophene‐S,S‐tetraoxide (BDTT) monomer as an acceptor and 3,4‐ethylenedioxythiophene flanked thiophene (TEDOT2) and terthiophene (T3) as donor molecules for polymer formation. The synthesis of thepoly(TEDOT2‐BDTT)andpoly(T3‐BDTT)copolymers was performed via a single‐step monomer radical formation that is typically associated with electropolymerization methods. The electropolymerization is controlled by using a suitable monomer stoichiometric ratio that enables the deposition of copolymer thin films on the working electrode. Resultant copolymers were investigated by electrochemical analysis and their electronic properties are discussed in detail. A low average electron transport resistance of 16.5 Ω was found forpoly(TEDOT2‐BDTT), indicating excellent conductive behavior. Solid‐state absorbance and emission studies of the copolymers show visible to near‐infrared spectral activity. Results support an effective strategy towards highly efficient electronically conducting polymers (ECPs) based on a unique BDTT monomer.

     
    more » « less
  5. Abstract

    3D‐printed hydrogel scaffolds functionalized with conductive polymers have demonstrated significant potential in regenerative applications for their structural tunability, physiochemical compatibility, and electroactivity. Controllably generating conductive hydrogels with fine features, however, has proven challenging. Here, micro‐continuous liquid interface production (μCLIP) method is utilized to 3D print poly(2‐hydroxyethyl methacrylate) (pHEMA) hydrogels. With a unique in‐situ polymerization approach, a sulfonated monomer is first incorporated into the hydrogel matrix and subsequently polymerized into a conjugated polyelectrolyte, poly(4‐(2,3‐dihydro‐thieno[3,4‐b][1,4]dioxin‐2‐ylmethoxy)‐butane‐1 sulfonic acid sodium salt (PEDOT‐S). Rod structures are fabricated at different crosslinking levels to investigate PEDOT‐S incorporation and its effect on bulk hydrogel electronic and mechanical properties. After demonstrating that PEDOT‐S does not significantly compromise the structures of the bulk material, pHEMA scaffolds are fabricated via μCLIP with features smaller than 100 µm. Scaffold characterization confirms PEDOT‐S incorporation bolstered conductivity while lowering overall modulus. Finally, C2C12 myoblasts are seeded on PEDOT‐pHEMA structures to verify cytocompatibility and the potential of this material in future regenerative applications. PEDOT‐pHEMA scaffolds promote increased cell viability relative to their non‐conductive counterparts and differentially influence cell organization. Taken together, this study presents a promising new approach for fabricating complex conductive hydrogel structures for regenerative applications.

     
    more » « less