Study on inkjet process variables in piezoelectric, drop-on-demand polymer inkjet printing

Abstract

Due to its simplicity, low cost, and flexibility, inkjet printing is now of great interest in its use in non-graphical applications such as light emitting diodes (LEDs), thin film transistors (TFTs), biochips, biosensors, drug delivery devices, and tissue engineering. The adaptation of polymer inks to a common inkjet system could make it possible to fabricate arbitrary, sophisticated, micro-patterned polymer architecture.

We studied how inkjet printability of polymers correlates processing variables such as viscosity, surface tension, contact angle, solvent composition, firing voltage, firing frequency, waveform, substrate temperature, nozzle temperature, etc. An FDA-approved biomedical polymer, polycaprolactone (PCL, MW 14,000) was used as a representative one. A piezoelectric, drop-on-demand (DOD) inkjet printer (Dimatrix Materials Printer, DMP-2800, Dimatrix Inc, USA) was used. All patterns are printed on flexible polyimide (PI) films. Through a systemic study with a variety of polymer inkjet variables, the polymer inkjet system was optimized.