A novel pattern transfer technique for mounting glassy carbon microelectrodes on polymeric flexible substrates
- Use inert-atmosphere pyrolysis @ 900 - 1000 C of 20um SU-8 (which is aromatic) on a thermal oxide wafer.
- Followed by spin & cure of PI.
- Demonstrate strong carbonyl bonding of the glassy carbon with mechanical and FTIR testing.
- Use of photosensitive PI allows through-vias to connect Cr/Au conductive traces.
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PMID-28084398 Highly Stable Glassy Carbon Interfaces for Long-Term Neural Stimulation and Low-Noise Recording of Brain Activity
- Use EIS to show superior charge-injection properties + stability of glassy carbon electrodes vs. Pt electrodes.
- GC lasted > 5e6 pulses; Pt electrodes delaminated after 1e6 pulses.
- Hydrogen bonding (above) clearly superior than neat PI-Pt interface
- GC electrodes were, true to their name, glassy and much smoother than the platinum electrodes.
- Further reduced impedance with PEDOT-PSS coating.
- PEDOT-PSS coating on glassy carbon was, in their hands, far more stable than PEDOT-PSS on platinum.
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- All devices, GC, PEDOT:PSS, and Pt, had similar biocompatibility in their assay (figure 7)
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