A highly sensitive printed humidity sensor based on a functionalized MWCNT/HEC composite for flexible electronics...

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Developing advanced materials for environmental monitoring is crucial.
• Functionalized carbon nanotubes offer unique properties for sensor applications.
• Hydroxyethyl cellulose provides a flexible matrix for composite materials.

Purpose of the Study:

• To develop a novel functionalized multi-walled carbon nanotube (FMWCNT)/hydroxyethyl cellulose (HEC) composite-based humidity sensor.
• To utilize additive print manufacturing for sensor fabrication.
• To evaluate the performance of the developed humidity sensor.

Main Methods:

• Covalent functionalization of multi-walled carbon nanotubes (MWCNTs) to enhance hydrophilicity.
• Formulation of a FMWCNT/HEC composite ink via solution blending.
• Fabrication of a multi-layered sensor on a polyethylene terephthalate (PET) substrate using screen and gravure printing.
• Characterization of FMWCNTs using TEM, Raman, and FTIR spectroscopy.

Main Results:

• The FMWCNT/HEC composite sensor exhibited a linear increase in resistance with increasing relative humidity (RH) from 20% to 80%.
• The sensor demonstrated a significant resistance change of approximately 290% at 80% RH compared to 20% RH.
• Achieved sensitivity of 0.048/%RH and a response time of approximately 20 seconds.

Conclusions:

• Additive print manufacturing is a feasible method for creating highly sensitive humidity sensors.
• The FMWCNT/HEC composite material shows promise for humidity monitoring applications.
• The developed sensor offers good performance characteristics for practical use.