Multifunctional Green Sensor Prepared by Direct Laser Writing of Modified Wood Component

The carbonization process of the cheap and renewable biomass sodium lignosulfonate (NaLS) as a green carbon sources by an in-situ environmentally friendly processing method-direct laser writing carbonization (DLWc)-was investigated. With various characterization methods the film formation conditions and laser processing parameters were investigated for their effect on physical and chemical structures, electrical, piezoresistive, and humidity response behaviors of the carbon patterns. Besides its intrinsic piezoresistivity, the resistance of the DLWc created carbon feature can also respond to moisture change. With these dual characteristics, the carbon patterns were successfully applied as piezoresistive and humidity sensors. A high gauge factor of 120 was achieved for the piezoresistive sensor made of a square-shaped carbon pattern. The work presented in this study indicates that the application of DLWc to carbonize NaLS can create green carbon patterns suitable for a variety of force and humidity related sensing applications.