A multimaterial 3D printing-assisted micropatterning for heat dissipation applications

Abstract

Micropatterned structures have applications in microchips, circuit board designs, micro uidics, evaporator/condenser coils, microelectronics, metasurfaces, and other functional devices. Conventional microfabrication techniques include lithography, vapor deposition, and laser writing. However, these methods have slow processing rates, complex requirements, or costly procedures. As a result, it is challenging to fabricate micropatterned structures onto large-scale surfaces with high production rates and resolution features. Thus, this study focuses on a non-conventional, mask-free micropatterning technique that combines bottom-up 3D printing capable of processing multiple materials and top-down wet etching for selective elimination of sacri cial material. The unique 3D printing, Multiphase Direct Ink Writing (MDIW), utilizes various polymer and nanoparticle systems as feedstocks for depositing lamellar structures containing sublayers of varying compositions (i.e., wet etchable sacri cial ink and ultravioletcurable patterning ink). The rapid phase transformation of photosensitive ink into solidi ed features enables "micro-con nement" of the sacri cial ink. Subsequently, wet etching can locally and selectively dissolve sacri cial polymers by solvent diffusion and polymer dissolution at the polymer-solvent interface. The parameter control (i.e., ink rheology, polymer-polymer interdiffusion, layer multiplication, phase transformation, and solvent-polymer interactions) can precisely tune the lamellar-groove transition, thus forming desirable surfaces or internal microstructures. Our MDIW 3D printing and its facilitation in surface micropatterning demonstrate the massive potential of distributing nanoparticles for dissipating thermal energies. With production scalability, operation simplicity, and multi-material compatibility, our 3D-printed micropatterning shows broader applications in nanoparticle assembly, drug delivery, optical lenses, intelligent microbots, and morphing objects.

Nozzle Innovations That Improve Capacity and Capabilities of Multimaterial Additive Manufacturing

“…After printing with the MDIW nozzle and subsequently etching away sacrificial material, microgrooves of epoxy laden with boron nitride particles were fabricated with a resolution between 50− 200 μm. 115 Micropatterning is achieved through a variety of techniques, most commonly lithography or vapor deposition. 126 However, this 3D-printing approach offers a simple, scalable, and cost-effective alternative.…”

“…UV curing of a permanent epoxy followed by wet etching of sacrificial poly(ethylenimine) ink yields a micropatterned ridged surface. Reproduced with permission from ref . Copyright 2023 the authors of ref , under exclusive license to Springer Nature Switzerland AG.…”

“…Reproduced with permission from ref . Copyright 2023 the authors of ref , under exclusive license to Springer Nature Switzerland AG.…”

“…Furthermore, the exceptional control of layer uniformity and size can be leveraged for micropatterning (Figure c). After printing with the MDIW nozzle and subsequently etching away sacrificial material, microgrooves of epoxy laden with boron nitride particles were fabricated with a resolution between 50–200 μm . Micropatterning is achieved through a variety of techniques, most commonly lithography or vapor deposition .…”

Three-Dimensional Printing of Lignocellulose Structures: Improving Mechanical Properties and Shape Fidelity

“…Three-dimensional (3D) printing, or additive manufacturing (AM) technology, creates physical objects from 3D models, usually layer-upon-layer patterns . This technology can quickly fabricate micro-to-macro-scale freestanding 3D structures without mold using single or multiple materials. , Depending on the materials, various AM techniques can be selected for fabricating 3D structures, including fused deposition molding (FDM), extrusion printing (EP), inkjet bioprinting, and powder fusion printing. − FDM and EP are the most attractive for printing thermoplastic, thermoset, and biopolymer composites among different AM techniques. In FDM, thermoplastic filaments of polycarbonates, polylactic acid, and acrylonitrile butadiene styrene melt at the nozzle into a semiliquid state and are extruded in a layerwise pattern to fabricate 3D structures. , In contrast, EP techniques can print precisely various materials, including thermosets and highly viscous wood-derived polymers such as nanocellulose under ambient conditions in a layerwise pattern …”