Replication of a Printed Volatile Mold: a novel microfabrication method for advanced microfluidic systems

Rémy Brossard,Thomas Brouchet,Florent Malloggi

doi:10.1038/s41598-019-53729-7

Abstract

A novel and simple method to fabricate microchannels is reported based on an inkjet printing of a volatile solid mold. A liquid ink -1,6 hexanediol- ejected from a piezoelectric nozzle is instantaneously frozen when touching a cooled substrate. The created mold is then poured with PDMS. Once the PDMS is crosslinked, the ink is sublimated and the device is ready. With this approach it is possible to make microchannels on different nature surfaces such as glass, paper, uncross-linked PDMS layer or non planar substrates. The versatility of this method is illustrated by printing channels directly on commercial electrodes and measuring the channel capacitance. Moreover, millimetric height microfluidic systems are easily produced (aspect ratio ge 25) as well as 3D structures such as bridges. To demonstrate, we have fabricated a combinatorial microfluidic system which makes 6 mixtures from 4 initial solutions without any stacking and tedious alignment procedure.

Highlights

Since the invention of the first devices in the late seventies[1,2], microfluidic technology has gained a lot of popularity
We found that the system can withhold 350mbar of pressure and breaks at 400 mbar which is sufficient for most microfluidic applications
We proposed a new method based on inkjet printing of a sacrificial material that can be removed in gas phase

Summary

Introduction

Since the invention of the first devices in the late seventies[1,2], microfluidic technology has gained a lot of popularity. Since 2004, many papers proposed methods where sacrificial molds are fabricated by either lithographic techniques[11,12] or 3D printing methods[13,14,15] After embedding these structures in the future chip material, the mold has to be removed, which is usually the most problematic part of the process. An inkjet printing method based on the engulfing of a liquid template has been proposed by Song et al.[19] This approach allows axisymmetric channel and fabricates systems in one step (no bonding), it is not possible to design arbitrary shapes and junctions are not easy to make. Making the synthesis of previous approaches, we propose an alternative method which is simple, versatile and modular It is based on the inkjet printing of a sacrificial material and its immersion in an appropriate cross-linkable material. It can be used in order to assemble any kind of element without the need of standardization

Methods

Results

Conclusion