Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, Vuorimiehentie 1, FI-00076 Espoo, Finland.
Sorbonne Université, CNRS, Laboratoire Interfaces et Systèmes Electrochimiques, LISE, UMR 8535, 75005 Paris, France.
ACS Appl Mater Interfaces. 2020 Aug 12;12(32):36437-36448. doi: 10.1021/acsami.0c09997. Epub 2020 Jul 30.
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.
TEMPO 氧化纤维素纳米纤维(TOCNF)和氧化碳纳米管(CNT)被用作湿度响应薄膜,并通过电声导纳(带阻抗监测的石英晶体微天平,QCM-I)和电阻率进行评估。在 30%至 60%的相对湿度(%RH)和 25 至 50°C 的温度范围内研究了水的吸收和溶胀现象。CNT 的存在使纤维网络具有高的水可及性,能够快速灵敏地响应湿度变化,质量增益高达 20%。基于 TOCNF 的传感器在吸水时表现出粘弹性,这可以通过 Martin-Granstaff 模型来定量。传感元件被支撑在玻璃和纸张基底上,并证实了在循环%RH、弯曲、粘附和耐久性方面具有广泛的工作窗口。支撑薄膜的电阻随%RH 从 20%到 60%的变化而增加约 15%。该系统具有监测智能包装中变化的巨大潜力。