Dodecylbenzenesulfonic acid dbsa

3-hexathiophene (3HT, 98.0% purity, TCI) was the starting monomer. Ferric chloride (FeCl₃; 97% purity, Sigma Aldrich, St. Louis, MO, USA) was the oxidant used. Chloroform (CHCl₃; AR grade, RCI Labscan, Bangkok, Thailand) was the solvent. Dodecylbenzenesulfonic acid (DBSA; 98% purity, Sigma Aldrich), p-toluenesulfonic acid (PTSA; 98.5% purity, Sigma Aldrich), sodium dioctyl sulfosuccinate (AOT; 96% purity, Sigma Aldrich), and sodium dodecyl sulfate (SDS; 98% purity, Sigma Aldrich) were the surfactants. Methanol (99.8%), toluene (99.5%), and hexane (99.8%) were obtained from RCI Labscan. For the de-doping and doping processes, ammonium hydroxide (NH₄OH; 30% v/v, Panreac, Barcelona, Spain) was used to de-dope the P3HT_DBSA powder, whereas perchloric acid (HClO₄; 70% v/v, Panreac) was the dopant. All reagents were of analytical reagent grades and were used without modification.

PEDOT:PSS aqueous suspension (Clevios PH1000) was purchased from Heraeus Electronic Material. Glycerol, dodecylbenzene sulfonic acid (DBSA), sodium chloride, (3-glycidyloxypropyl) trimethoxysilane (GOPS), acrylamide (AAm), calcium chloride (CaCl₂), and 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) were purchased from the Sigma-Aldrich (USA). Hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure 2959), glutaraldehyde, aminoferrocene, GOx, and chitosan were provided by Aladdin Co. (Shanghai, China). The PI thin film was obtained from the DuPont Co. (USA). The biocompatible adhesive polyurethane was provided by 3M (USA). Unless otherwise specified, the chemicals in the current work were used without further purification.

PEDOT:PSS (Heraeus, Clevios PH1000) was used as the conducting polymer active layer. 50 µL mL⁻¹ ethylene glycol (average M_W 62.07 g mol⁻¹, Sigma Aldrich) and 0.5 µL mL⁻¹ dodecylbenzenesulfonic acid (DBSA, average M_W 326.49 g mol⁻¹, Sigma Aldrich) were added to the PEDOT:PSS dispersion to increase the conductivity and improve the film structure. A 10 wt% solution of PVA (average M_W 130 000, Sigma Aldrich) was prepared by sonicating a PVA:deionized water mixture until a clear solution was obtained. 25 µL mL⁻¹ of 10 wt% PVA was later added to the above PEDOT:PSS dispersion followed by sonication for 1 h. In the final step, 0.25 wt% (3‐glycidyloxypropyl)trimethoxysilane (GOPS) (M_w 236.34 g mol⁻¹, Sigma Aldrich) was added to improve the adhesion of the polymeric film to glass substrates. For the PEDOT:PSS solution not containing PVA, 1 wt% GOPS was added instead. The above mixture was then sonicated again for 30 min before being filtered through a 0.45 µm PVDF filter to avoid aggregates.