Surfaces with stimuli-responsive microstructures have aroused great attention in past years. However, it remains challenging to endow a surface with the capability of accurate local control of the microstructures geometrical morphology to realize applications that require remote, selective and on-demand responses. Here, we demonstrate a kind of carbonyl iron particles (CIPs) doped shape memory micropillar arrays for accurately controllable switching between the bend and upright state under pressure and near-infrared light (NIR) irradiation. Thus, we imparted the surface with a reversible transition between a smooth state with bend microstructures demonstrates low friction coefficient of ~0.8 and a rough state with upright microstructures demonstrates high friction coefficient of ~1.2 as the remotely and accurately tunable friction, in addition, we show that the friction on the surface can be programed reversibly by simple adjusting NIR irradiation pathways. We demonstrated these programmable friction pathways to not only accurately adjust the friction coefficient in the target area but also to provide friction control platform for different purposes, such as microsolid separation. Moreover, the water droplet adhesion force of the surface can be reversibly switched between ~160 μN and ~760 μN, demonstrating the application potential in accurately controllable wettability. These features indicated that the NIR accurately controllable shape memory micropillars would be amenable to a variety of applications, such as micro-particle motion control, lab-on-a-chip and microfluidics.

NIR triggered reprogrammable shape memory micropillars with accurately controllable friction and adhesion

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.