Micro suction cup array for wet/dry adhesion

We propose a micro suction cup array for adhesion to both dry and wet surfaces. We measured the peel-off forces of a PDMS micro suction cup array, a PDMS flat-tip micro structure array and a flat PDMS pad from both wet and dry glass surfaces. When the glass surface was wet, the peel-off forces of a PDMS flat-tip micro pattern and a flat PDMS pad decreased by more than 1.7 times and 7.0 times, respectively. On the other hand, peel-off forces of a PDMS micro suction cup array increased by over 1.1 times when the glass surface was wet. Also, in both wet and dry conditions, an array of PDMS micro suction cup adhered stronger to a glass surface than a PDMS flat-tip micro pattern and a flat PDMS pad. Furthermore, we demonstrated that the adhesion of a suction cup array can be enhanced by miniaturizing the size of the cups.