Highly Stretchable Potentiometric pH Sensor Fabricated via Laser Carbonization and Machining of Carbon−Polyaniline Composite

Rahim Rahimi, Manuel Ochoa, Ali Tamayol, Shahla Khalili, Ali Khademhosseini, Babak Ziaie

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


The development of stretchable sensors has recently attracted considerable attention. These sensors have been used in wearable and robotics applications, such as personalized health-monitoring, motion detection, and human-machine interfaces. Herein, we report on a highly stretchable electrochemical pH sensor for wearable point-of-care applications that consists of a pH-sensitive working electrode and a liquid-junction-free reference electrode, in which the stretchable conductive interconnections are fabricated by laser carbonizing and micromachining of a polyimide sheet bonded to an Ecoflex substrate. This method produces highly porous carbonized 2D serpentine traces that are subsequently permeated with polyaniline (PANI) as the conductive filler, binding material, and pH-sensitive membrane. The experimental and simulation results demonstrate that the stretchable serpentine PANI/C-PI interconnections with an optimal trace width of 0.3 mm can withstand elongations of up to 135% and are robust to more than 12 000 stretch-and-release cycles at 20% strain without noticeable change in the resistance. The pH sensor displays a linear sensitivity of −53 mV/pH (r2 = 0.976) with stable performance in the physiological range of pH 4-10. The sensor shows excellent stability to applied longitudinal and transverse strains up to 100% in different pH buffer solutions with a minimal deviation of less than ±4 mV. The material biocompatibility is confirmed with NIH 3T3 fibroblast cells via PrestoBlue assays.

Original languageEnglish (US)
Pages (from-to)9015-9023
Number of pages9
JournalACS Applied Materials and Interfaces
Issue number10
StatePublished - Mar 15 2017
Externally publishedYes


  • electrochemical sensors
  • laser carbonization
  • porous carbon
  • stretchable
  • wearable point-of-care

ASJC Scopus subject areas

  • Materials Science(all)

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