Laser-ablated acoustofluidics-driven paper devices for controllable chemical engineering in color display applications.

[Display omitted] • Gentle power of laser was used to do surface modification of paper substrates. • Effects of different types of lasers including CWL, NS, and FS were studies. • Physical and chemical changes of laser-ablated paper were investigated. • Aldehydes were produced by laser ablation and raised the paper's chemical reactivity. • Aldehydes-related color chemical reactions were performed with acoustofluidic PADs. Paper-based analytical devices (PADs) have rapidly thrived in the last decade for their easy operation and rapid response. However, because of its low chemical reactivity, it's still challenging to endow the paper substrate with more functions and expand its application field. Here, this work leverages lasers to do surface modifications of paper to raise its chemical reactivity. A gentle power of laser was utilized to ablate a part thickness of the paper. The effect of laser types was studied, including continuous-wave, nanosecond, and femtosecond lasers. Continuous-wave laser caused severe photothermal effects and produced more pyrolytic oil. The physical changes including mechanical strength and fluid wicking were studied. The chemical changes were analyzed by XPS and FTIR. Because of the produced aldehydes by laser ablation, the laser-modified papers were endowed with more functions and we experimented with aldehyde-related color reactions on them, which might promote the color printing industry. In addition, to fully exploit the produced aldehydes, our recently developed acoustofluidic PADs were employed for flow intensification and homogeneous mixing. This work demonstrates an economical and effective method for a new type of functional paper substrates which holds potential for various fields. [ABSTRACT FROM AUTHOR]