Electrically Conductive Thin Films Based on Nanofibrillated Cellulose: Interactions with Water and Applications in Humidity Sensing

Katariina Solin, Maryam Borghei, Ozlem Sel (Corresponding Author), Hannes Orelma, Leena Sisko Johansson, Hubert Perrot, Orlando J. Rojas (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

Abstract

TEMPO-oxidized cellulose nanofibrils (TOCNF) and oxidized carbon nanotubes (CNT) were used as humidity-responsive films and evaluated using electroacoustic admittance (quartz crystal microbalance with impedance monitoring, QCM-I) and electrical resistivity. Water uptake and swelling phenomena were investigated in a range of relative humidity (% RH) between 30 and 60% and temperatures between 25 and 50 °C. The presence of CNT endowed fibril networks with high water accessibility, enabling fast and sensitive response to changes in humidity, with mass gains of up to 20%. The TOCNF-based sensors became viscoelastic upon water uptake, as quantified by the Martin-Granstaff model. Sensing elements were supported on glass and paper substrates and confirmed a wide window of operation in terms of cyclic % RH, bending, adhesion, and durability. The electrical resistance of the supported films increased by ∼15% with changes in % RH from 20 to 60%. The proposed system offers a great potential to monitor changes in smart packaging.

Original languageEnglish
Pages (from-to)36437-36448
Number of pages12
JournalACS Applied Materials & Interfaces
Volume12
Issue number32
DOIs
Publication statusPublished - 12 Aug 2020
MoE publication typeA1 Journal article-refereed

Keywords

  • carbon nanotubes
  • conductive ink
  • humidity sensing
  • nanocellulose
  • quartz crystal microbalance with impedance measurement (QCM-I)
  • viscoelastic properties
  • water interactions

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