Thermally cross-linkable photo-hydrolyzable inkjet printable polymers for microfluidic channels

摘要

Thermally cross-linkable photo-hydrolyzable inkjet printable polymers are used to print microfluidic channels layer-by-layer on a substrate. In one embodiment, for each layer, an inkjet head deposits droplets of a mixture of hydrophobic polymer and cross-linking agent in a pattern lying outside a two-dimensional layout of the channels, and another inkjet head deposits droplets of a mixture of poly(tetrahydropyranyl methacrylate) PTHPMA (or another hydrophobic polymer which hydrolyzes to form a hydrophilic material), cross-linking agent, and a photoacid generator (PAG) in a pattern lying inside the two-dimensional layout of the channels. After all layers are printed, flood exposure of the entire substrate to UV radiation releases acid from the PAG which hydrolyzes PTHPMA to form hydrophilic poly(methacrylic acid) PMAA, thereby rendering the PTHPMA regions hydrophilic. The layers of these now-hydrophilic patterned regions together define the microfluidic channels. The cross-linking agent (e.g., triallyl isocyanurate TAIC) forms covalent cross-links between the two polymer phases.

主权项

1. A composition contained in a reservoir of an inkjet cartridge for fabricating microfluidic channels, consisting of:
a second mixture in the reservoir of the inkjet cartridge for supply to a second inkjet head, the second mixture consisting of poly(tetrahydropyranyl methacrylate) (PTHPMA), a cross-linking agent, and a photoacid generator, wherein the second mixture contains less than 2 wt % of the photoacid generator and 2 to 5 wt % of the cross-linking agent; wherein the cross-linking agent includes a multi-functional thermally cross-linkable monomer that is capable of copolymerizing with both a hydrophobic polymer contained in a first mixture and the PTHPMA to form covalent cross-links between the hydrophobic polymer and the PTHPMA when the first mixture and the second mixture are placed in contact with one another upon being deposited on a substrate by a first inkjet head and the second inkjet head, respectively, and exposed to heat.