A flexible IrO2 membrane for pH sensing

Shih Cheng Chou, Yi Chieh Hsieh, Wai Hong Cheang, Bo Yao Sun, Chao Yi Chu, San Yuan Chen, Jung Chih Chiao, Pu Wei Wu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


An optimized mixture of polydopamine (PDA) and polyvinyl alcohol (PVA) is employed as the surface functionalizing agent and reducing agent to encapsulate individual polypropylene (PP) fibers of polypropylene micromembrane (PPMM). The functionalized PPMM becomes hydrophilic to allow the formation of Au nuclei for subsequent electroless Au deposition. The metalized PPMM is further deposited with IrO2 nanoparticles, and evaluated as a flexible and porous pH sensor. Images from scanning electron microscope confirms the uniform formation of IrO2 nanoparticles on Au-coated PP fibers. For pH-sensing performance, the IrO2-decorated metalized PPMM reveals a super-Nernstian response for a sensing slope of -74.45 mV/pH in aqueous solutions with pH value ranging between 2 and 12. In addition, the pH-sensing performance is properly maintained after 5000 bending cycles and hysteresis is modest in an acidic environment. The cell viability test indicates a negligible bio-toxicity. Our strategy of using a conductive polymeric membrane decorated with IrO2 nanoparticles enables possible sensing applications in wearable and implantable electronics.

Original languageEnglish
Article number11712
JournalScientific reports
Issue number1
StatePublished - Dec 2022


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