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A highly conductive and ultra-stretchable polyaniline/cellulose nanocrystal/polyacrylamide hydrogel with hydrophobic associations for wearable strain sensors

Rahmani, P ; Sharif University of Technology | 2024

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  1. Type of Document: Article
  2. DOI: 10.1039/d3ta07424b
  3. Publisher: ACS , 2024
  4. Abstract:
  5. Despite tremendous attention to hydrogel-based wearable strain sensors, it is still challenging to develop an all-in-one hydrogel possessing desired properties of ultra-stretchability, extraordinary conductivity and high strain sensing. Herein, instead of conventional chemical cross-linking, polyacrylamide (PAAm) hydrogel is cross-linked with hydrophobic association (HA), and is further reinforced with cellulose nanocrystals (CNCs), yielding a robust HAPAAm/CNC hydrogel. Subsequently, the HAPAAm/CNC is sequentially immersed into acidic solutions with various concentrations of aniline and initiator (0.5 M is optimal), leading to polymerization of aniline monomers inside the hydrogel. The optimal hydrogel (HAPAAm/CNC/polyaniline (PAni)-0.5), has great stretchability (≈2400%) and skin-like Young's modulus (30 kPa). It also shows outstanding electrical conductivity (21.7 S m−1), thanks to conductive pathways provided by PAni nanofibers. Such a combination of great mechanical and electrical properties has never been reported for PAni-based hydrogels. The resultant hydrogel can sense strains as low as 1%, while also measuring strains up to 1000%. Besides having linearity, the hydrogel sensor has a high gauge factor (GF = 3.7) within a range of 0-200%, exceeding that of many reported PAni-based hydrogel sensors. The hydrogel sensor can detect human motions from large strains to minor ones (e.g., breathing). Therefore, HAPAAm/CNC/PAni-0.5 shows great promise for soft electronics. © 2024 The Royal Society of Chemistry
  6. Keywords:
  7. Aniline ; Cellulose ; Conductivity ; Sensors ; Strains ; Stretch ; Water Repellence ; Aniline ; Crosslinking ; Nanocrystals
  8. Source: Journal of Materials Chemistry A ; Volume 12, Issue 16 , 2024 , Pages 9552-9562 ; 20507488 (ISSN)
  9. URL: https://pubs.rsc.org/en/content/articlelanding/2024/ta/d3ta07424b/unauth