Blood-repellent properties of picosecond laser-constructrued micropillar array surfaces in DC/AC electric fields

Abstract

The application of superhydrophobic surfaces to prevent blood adhesion to medical devices has attracted widespread attention from researchers, especially in electrosurgery. In this study, we used one-step picosecond-laser processing and subsequent fluorination to construct a micropillar array surface on multicracked substrates and achieve superhemophobicity. The formation of this surface and the effects of both the micropillars' diameter and spacing on the blood-repellent properties were analyzed. The results indicated that increasing both the diameter and spacing decreases the blood droplet contact angle, while changing the spacing substantially impacts the dynamic repellency. Furthermore, the evolution of blood droplets on the micropillar array surfaces was investigated in direct/alternating current (AC) electric fields. Structural gaps enabled electrolysis-generated gases to escape downward, preventing blood expansion. Because of the oscillatory effect, AC excitation changes the blood droplets' morphology, which drives the gas–liquid interface toward the multicracked substrate; however, trapped gas impedes this negative behavior. Additionally, water droplets aggregated, and the aggregation mechanism was revealed. This study contributes to mitigating blood adhesion on electrosurgical instruments.