Fabrication of monolithic polymer nanofluidic channels via near-field electrospun nanofibers as sacrificial templates

This paper reports a facile and maskless method for fabricating nanofluidic channel arrays using near-field electrospinning (NFES) templates with prescribed patterns and the polydimethylsiloxane (PDMS) molding technique. Nanochannels were fabricated monolithically through three main steps: 1) direct-writing nanofiber arrays onto a silicon substrate using NFES, 2) PDMS molding of the prescribed nanofibers patterns, and 3) plasma treating PDMS substrate to promote the adhesion and bonding process. The nanochannels fabricated in this study had channel widths ranging from 500 to 1300 nm and depths of 70 to 500 nm, and were patterned in a fashion similar to the wire bonding process routinely used in the semiconductor industry. The nanochannel dimensions were predominantly dictated by electrospun nanofibers, showing that NFES is capable of depositing nanofibers with a diameter down to -50 nm. Results show that reliable and repeatable nanofluidic channel arrays were speedily fabricated at a very low cost, while nanofluidic patterns and dimensions are predominantly controlled by NFES in a directwrite, addressable manner.