Blister-actuated laserinduced forward transfer

Laser-induced forward transfer (LIFT) is an established direct-write technique that enables the deposition of a range of solid, complex multiphase, and liquid inks from a donor to a receiver substrate. Material transfer typically occurs via direct vaporization of ink material or by the complete vaporization of a thin (50-500 nm) sacrificial layer in contact with the ink. This thesis presents the development of a blister-actuated LIFT variant (BA-LIFT), comprised of a thick (2-10 mum) polymer layer, that eliminates the direct laser/ink interaction, and is characterized by a purely mechanical mechanism for ink transfer. Finite element analysis is used to model the dynamic response of the laser-generated micron-sized blisters and model validation is through comparison to time-resolved experimental results. Strain-rate-dependent polymer properties and the conversion efficiency of laser energy to enclosed blister pressure are determined. Higher laser energy blister rupture is accurately captured via a strain-based failure approach. In addition, the effect of laser beam shape on polymer deformation is investigated revealing new and interesting dynamics.;The second part of this thesis is a case study on the application of BA-LIFT for the printing of organic and biological materials that are susceptible to optical, thermal, and mechanical damage. The mechanisms for transfer associated with standard LIFT variants and BA-LIFT are investigated through the characterization of damage in printed light-emitting organic molecules. Damage free BA-LIFT transfers of delicate organic molecules are exhibited in the confined blister regime and in the higher energy blister rupture regime. These results offer a fundamental understanding of thermal transport to ink material during BA-LIFT, and are used to elucidate the predominant mechanisms for damage present in the organic molecule. However, damage to delicate embryonic stem cells is observed to increase during blister rupture. In this instance, the pressures and temperatures of the ruptured blisters cause damage to the more susceptible cells. Finally, the versatility of BA-LIFT is demonstrated by fabricating organic light-emitting devices and high-resolution patterns of organic light-emitting molecules. Results are presented and discussed in terms of newer processing technologies to enable the study of structure-function relationships for small organic molecules in parallel with their development.