3 glycidyloxypropyl trimethoxysilane gops

PEDOT: PSS dispersion was purchased from Sigma-Aldrich (Product number: 483095, CAS number 155090-83-8, Sigma-Aldrich, MO, United States). The nominal solid content and the PEDOT to PSS ratio of the PEDOT: PSS dispersion were 1.3% and 1:1.6 by weight, respectively. (3-Glycidyloxypropyl) trimethoxysilane (GOPS, Sigma-Aldrich, MO, United States) was used as received without further purification. 3,4-Ethylenedioxythiophene (EDOT) and polysulfate sodium (NaPSS) were obtained from Sigma Aldrich (MO, United States) and used to obtain the solution (EDOT 0.01 M; NaPSS 0.8% w/w) for the electrochemical deposition of PEDOT: PSS. Borosilicate glass slides (thickness ∼1 mm, Thermo Scientific, MA, United States) were used as substrate for the deposition of the PEDOT: PSS films by spin coating after ultrasonic cleaning in a mixed solution of pure ethanol, isopropanol and milliQ water (1:1:1 by volume) and drying under sustained flux of pure nitrogen. Fluorine Tin Oxide (FTO) slabs (1.5 × 1 cm², thickness ∼1 mm) were used as conductive substrate for the electrochemical polymerisation of PEDOT:PSS films. FTO slabs were used after ultrasonic cleaning in a solution of pure ethanol and milliQ water (1:1), drying under sustained flux of pure nitrogen and a heating step at 450°C for 30 min in order to clean the surface from organic residues and after cooling overnight in the muffle.

The investigated silicone (Sil) and Pt-contact samples were provided by MED-EL (Innsbruck, Austria). All silicone samples used in this study contained 5 wt% DMS, which was added during the manufacturing process.
Poly-L-lactide (PLLA, L210) was purchased from Evonik (Schwerte, Germany). The crosslinker (3-glycidyloxypropyl)trimethoxysilane (GOPS) was purchased from Sigma-Aldrich (Taufkirchen, Germany) and PLLA-NH₂ was provided by VWR (Dresden, Germany).

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.