3D printing of multi-scalable structures via high penetration near-infrared photopolymerization

Abstract

3D printing consisted of in-situ UV-curing module can build complex 3D structures, in which direct ink writing can handle versatile materials. However, UV-based direct ink writing (DIW) is facing a trade-off between required curing intensity and effectiveness range, and it cannot implement multiscale parallelization at ease. We overcome these difficulties by ink design and introducing near-infrared (NIR) laser assisted module, and this increases the scalability of direct ink writing to solidify the deposited filament with diameter up to 4 mm, which is much beyond any of existing UV-assisted DIW. The NIR effectiveness range can expand to tens of centimeters and deliver the embedded writing capability. We also demonstrate its parallel manufacturing capability for simultaneous curing of multi-color filaments and freestanding objects. The strategy owns further advantages to be integrated with other types of ink-based 3D printing technologies for extensive applications.

NIR‐Sensitized Cationic and Hybrid Radical/Cationic Polymerization and Crosslinking

“…Furthermore, up‐conversion nanoparticles with the capability to generate UV‐light showed acceptable performance to initiate free radical polymerization of systems comprising UV initiators applying a 980 nm laser [32–35] . Remarkable results achieve deep curing lengths applying free radical polymerization, [34, 36] while the first report of an ATRP mechanism based on a metal‐free system appeared in 2017 [33] …”

3D printing of tissue engineering scaffolds: a focus on vascular regeneration

“…And UV-assisted 3D printing is limited by crosslinkable print materials and low light penetration. Both computational axial lithography and near-infrared photopolymerization significantly improve the preparation rate of vascular scaffolds [ 104 , 135 ]. But there are fewer reports on these methods.…”

“…But most of photosensitive materials are suitable for UV light. Near-infrared light improves the penetrability and the ranges of photopolymerization and printability of color structures [ 135 ]. Recently, the conversion of near-infrared light to UV light has been reported using up-conversion nanoparticles [ 106 ].…”

Epoxy Based Blends for Additive Manufacturing by Liquid Crystal Display (LCD) Printing: The Effect of Blending and Dual Curing on Daylight Curable Resins

“…Daylight resins cure at 460 nm while most of the other photocurable resins cure in the UV region using wavelengths between 325-420 nm. According to Photocentric, "the use of light at longer wave length proved to allow for a deeper penetration depth into the photopolymer material and therefore a more uniform and accurate 3D printing process" [9,10]. The combination of visible light with the use of LCD screens for 3D printing, allows for a faster, more efficient and economical manufacturing process.…”