Gradient induced liquid motion on laser structured black Si surfaces

TL;DR

This paper demonstrates femtosecond laser fabrication of gradient-wettability patterns on silicon, enabling high-speed droplet spreading and potential applications in microfluidics, fuel cells, and drug delivery.

Contribution

It introduces a novel laser patterning method to create surface tension gradients on silicon with record droplet spreading speeds.

Findings

Maximum droplet spreading speed of 505 mm/sec.

Laser patterned surfaces achieve high-speed liquid motion.

Potential for applications in microfluidic systems and energy devices.

Abstract

This letter reports on the femtosecond laser fabrication of gradient-wettability micro/nano- patterns on Si surfaces. The dynamics of directional droplet spreading on the surface tension gradients developed is systematically investigated and discussed. It is shown that microdroplets on the patterned surfaces spread at a maximum speed of 505 mm/sec, that is the highest velocity demonstrated so far for liquid spreading on a surface tension gradient in ambient conditions. The application of the proposed laser patterning technique for the precise fabrication of surface tension gradients for open microfluidic systems, liquid management in fuel cells and drug delivery is envisaged.