Fig. 6. The effect of the size of the superhydrophilic pattern on the concentration process of droplets.

a SEM images of patterned superhydrophilic surfaces with different diameters, which from left to right are 600, 500, 400, 300, 200, and 100 μm. b Final concentrated diameter for superhydrophilic patterns with different diameters. c Raman spectra of a 10⁻¹⁰ M R6G solution on surfaces with different superhydrophilic pattern diameters