FIG. 4.

Illustration of the effect of the microchannel aspect ratio (h/w) on the microchannel radius of curvature (r). Symbol d denotes the nominal thickness of the microchannel layer. The difference between the nominal thickness (d) and the measured height (h) is the residual layer thickness. (a) The microchannel radius of curvature (r) as a function of aspect ratio under a constant UV exposure dose of 19 mJ/cm² or 29 mJ/cm² and a proximity gap of 400 μm. (b) SEM images of the cross-sectional shapes produced with aspect ratios of 0.35 (nominal channel width 100 μm and layer thickness 35 μm) and 0.9 (nominal channel width 50 μm and layer thickness 45 μm).