Polydimethylsiloxane microlenses fabricated from liquid-phase photopolymerization and single molding step

Abstract

We report on polydimethlysiloxane (PDMS) microlenses fabricated from liquid-phase photopolymerization and a single molding step. The mold is fabricated by photopolymerizing a polyacrylamide (PAAm) pre-hydrogel flowed into an aperture array with a channel underneath. PAAm shrinks isotropically while pinned around the rim of the apertures to form lens molds due to hydrophobic-hydrophilic boundaries. The lenses are then transferred to PDMS by a singlestep molding. The microlenses can be fabricated in different sizes and into arrays without extensive control of fabrication parameters. As an example, we show characterization of fabricated microlenses with a diameter of 1 mm and calculated focal length of 2.83 mm. The surface roughness of the microlenses is on the order of 150nm.