Organic Nanocomposite Structure Tailored by Controlling Droplet Coalescence during Inkjet Printing

Abstract

Inkjet printing offers a low-cost, high-throughput avenue for producing functional organic materials through rapid translation of desktop discoveries to industrial roll-to-roll processes. Here, we report a simple, but effective strategy to control droplet coalescence during inkjet printing, as a major variable, to tailor the nanoscale morphology of organic composite materials produced upon evaporation of all-liquid inks. During deposition, the spacing between ink droplets was controlled to systematically vary the extent of droplet coalescence. Our results show that decreasing coalescence increased the solvent evaporation rate, supersaturation of the solutes, and nucleation density of the precipitating organic crystals. This phenomenon was utilized to tailor the average size of pentaerythritol tetranitrate (PETN) crystals dispersed in an adhesive binder matrix from ~0.2 to upwards of 100 μm. The results suggest that controlling the extent of droplet coalescence can be used as an effective means to tailor the composite morphology of printed organic materials at the nanoscale.

Progress in Additive Manufacturing of Energetic Materials: Creating the Reactive Microstructures with High Potential of Applications

“…Ihnen and coworkers, in a series of papers [62,68,69], explored a nonslurry material, i. e., a solution, for printing. Explosive ink comprises RDX solution in dimethylformamide (DMF) and a polymeric binder (cellulose acetate butyrate CAB, polyvinyl acetate).…”

“…For a single-nozzle system without heating the substrate, this value is extremely low at~100 μm per week, increasing to 2-30 μm h À 1 when the heating is applied [68,73]. Further improvement can be attained using a multinozzle system; however, the lowering of the distance between droplets promotes the pooling effect, as illustrated by Figure 4b, where the linear structure is printed at a minimal spacing [69]. The coffee-ring phenomenon is evident again, leading to an increase in the line width from the diameter of a drop (50 μm) to 190 μm.…”

“…Bottinger et al proposed introducing an additional unit -an ink jet aerosol generator [74], which represents the drying tube for controlled single-or multiparticle delivery, i. e., single-particle printing. This design was theoretically and experimentally discussed and was applied to energetic [68] with permission from Elsevier, (b) reprinted from [69] with permission from the American Chemical Society. materials by a team from the National Institute of Standards and Technology [74].…”

Direct Ink Writing of DNTF Based Composite with High Performance

“…In recent years, some CL-20 based formulations was continuously appeared in literatures [7][8][9]. However, the development of allliquid explosive ink was relatively less, only Ihnen et al studied the tailoring of morphology by controlling processing technics [10][11][12].…”

Vortex formation in coalescence of droplets with a reservoir using molecular dynamics simulations

“…18 Technical applications of droplet coalescence include inkjet-printing, 9,10 surface cleaning, 11 coating, 12,13 and microuidic devices. 14 Investigating the mechanism of spreading a liquid drop on a liquid subphase is also relevant for medical applications such as transporting drugs through the lungs tissue.…”