Fabrication of a bunch of sub-30-nm nanofibers inside microchannels using photopolymerization via a long exposure technique

Abstract

Experimental studies on the fabrication of sub-30-nm nanofibers using two-photon initiated photopolymerization (TPP) have been carried out. To generate nanofibers at the interior region of microstructures, a photopolymerization method involving a long laser-exposure technique (LET) is proposed. A multitude of nanofibers with a notably high resolution (about 22nm) in TPP were produced using the LET. Furthermore, it is also demonstrated that thin interconnecting networks were created regularly in a weakly polymerized region existing around the boundary of a densely polymerized voxel, allowing for the creation of various embossing patterns. By controlling the distance between adjacent voxels or lines, a selective generation of nanofibers in a local area is possible, which leads to the fabrication of high-functional filters and mixers. Embossing patterns and microchannels including nanofibers inside were fabricated by the LET so as to demonstrate the practical feasibility of this approach. These sub-30-nm nanofibers may find meaningful applications such as biofilters, mixers, and photon emitters in diverse research fields.