Conductive inks based on methacrylate end‐capped poly(3,4‐ethylenedioxythiophene) for printed and flexible electronics

Abstract

A new synthesis of methacrylate end‐capped poly(3,4‐ethylenedioxythiophene) (PEDOT) was performed: the polymer is soluble in common organic solvents, thus overcoming the well‐known technical problems related to the use of commercial PEDOT in different printing technologies, such as screen printing, due to its poor processability and compatibility in formulations with other resins and polymers. The new synthetic method developed is based on the direct oxidative polycondensation of 3,4‐ethylenedioxythiophene (EDOT) in the presence of an oxidant species and a crosslinkable end‐capper, i.e., methacrylate end‐capped EDOT (mEDOT), prepared via Friedel Crafts acylation with methacryloyl chloride. The oxidative polycondensation between EDOT and mEDOT monomers in the presence of a new kind of doping agent, Sulfonated Polyarylethersulfone (SPES)—characterized by different degree of sulfonation (DS)—was conducted, leading to functional end‐capped conducting PEDOT (mPEDOT_SPES), with conductivity of 210 S/cm, 50 S/cm higher than the one of commercial PEDOT. Thanks to the enhancement of solubility, leading to better processability, end‐capped PEDOTs were formulated with a thermoplastic ink, Plastisol®, and electronic circuits were successfully screen printed on flexible cotton substrates, to obtain printed crosslinkable electronic circuits. The conductive features of mPEDOT_SPESs were successfully compared with the ones of PEDOT and of not‐doped end‐capped PEDOTs. POLYM. ENG. SCI., 57:491–501, 2017. © 2017 Society of Plastics Engineers

A Combined XRD, Solvatochromic, and Cyclic Voltammetric Study of Poly (3,4-Ethylenedioxythiophene) Doped with Sulfonated Polyarylethersulfones: Towards New Conducting Polymers

“…3,4-Ethylenedioxythiophene (EDOT, >97%, stored at +5 • C), 2-naphthalenesulfonic acid (Naph, >70%), ferric sulfate (Fe 2 (SO 4 ) 3 ·xH 2 O, >97%), 4,4 -difluorodiphenylsulfone (BFPS, ≥99%), and 4,4 -dihydroxydiphenyl (BHP, ≥97%) were supplied by Sigma Aldrich (Milan, Italy) and used without further purification and EDOT purity was checked via FT-IR and 1 H NMR spectra [22]. 2,5-Dihydroxybenzene-1-sulfonate potassium salt (sulfonated hydroquinone, SHQ, ≥98%) was obtained from Alfa Aesar (Karlsruhe, Germany) and potassium carbonate (K 2 CO 3 , ≥98% anhydrous) was purchased from Fluka (Milan, Italy Four PEDOTs obtained using different reaction solvents, namely, DMF, DMAc, DMSO, and NMP, were synthesized.…”

“…After drying in a vacuum oven (about 4 mbar) at 200 • C for 24 h, the thermal stability of PEDOT_SPAESs samples was estimated via thermogravimetric analyses (TGA) evaluating temperatures corresponding to 1%, 5%, and 10% of weight loss (T 1% , T 5% , and T 10% ) and comparing results obtained with TGA data of PEDOTs and PEDOT_Naphs used as references (Table 3). DSC and TGA thermograms corresponding to the data presented are reported in according with our previous work [22]. Table 3.…”

“…The polymeric solutions obtained are completely soluble in all four solvents and appear in different colors as shown in Figure 2. All samples were dried in a vacuum oven and the overall compositions were measured via 1 H NMR spectra [22].…”

“…The polymeric solutions obtained are completely soluble in all four solvents and appear in different colors as shown in Figure 2. All samples were dried in a vacuum oven and the overall compositions were measured via 1 H NMR spectra [22]. In addition to the reported PEDOT dopants, SPAES can also be used as a PEDOT doping agent thanks to the possibility to appropriately modulate the number of sulfonic groups and to tailor R-SO3 − groups' distribution homogeneity along the polymeric chains.…”

“…In our previous works [22,43], PEDOT_SPAES thin films were tested for their conductivity, as conductive inks for organic electronics. The research conducted leads to modified PEDOT polymers with conductivity of 210 S·cm −1 , 50 S·cm −1 higher than the one of commercial PEDOT.…”