A study of meniscus formation and its effect on roll-to-roll UV embossing

This work investigates the meniscus formation in the microstructures fabricated via a roll-to-roll ultraviolet (UV) embossing process. Experiments are carried out to investigate the effect of meniscus formation on the embossing process. Characterizations of the embossed microstructures are performed. The study found that if the resin volume is not sufficient to fill up the micro cavities completely, the embossed microstructures after UV curing may demonstrate “volcano” profiles. This is because the resin fills the cavities first along the pillar sidewalls of the mould due to the good surface wettability. By adjusting the slot-die coater pressure, the coating thickness can be controlled, the resin can completely fill mould cavities, the meniscus formation can be avoided, and a perfect negative copy of the mould on the embossed substrate can be obtained.