UV-Resistant Self-Healing Emulsion Glass as a New Liquid-like Solid Material for 3D Printing

Abstract

Directly writing 3D structures into supporting mediums is a relatively new developing technology in additive manufacturing. In this work, durable and recyclable liquid-like solid (LLS) materials are developed as supporting mediums that are stable for both UV and thermal solidification. Our LLS material is comprised of densely packed oil droplets in a continuous aqueous medium, known as emulsion glass. Its elastic nature emerges from the jammed structure of oil droplets, which offers this LLS material rapidly self-healing ability. Moreover, the yield stress of the glass is relatively low and can be tuned by the viscosity and weight percentage of oil. The capability of the emulsion glass as supporting mediums is successfully demonstrated by directly writing and then curing designed structures. The emulsion glass has been repeatedly used at least 6 times upon exposure to UV irradiation and heat, implying it can expand the applications of supporting medium to the writing process involving UV- and thermal-curable inks simultaneously.

Fabricating Robust Constructs with Internal Phase Nanostructures via Liquid‐in‐Liquid 3D Printing

“…Removal of all printed constructs, whether helices, letters, scaffold, or thin threads from the oil phase is carried out with no break or failure (Figure 1e,g), and without the need for any change in oil phase condition such as addition of a buffer solution or temperature adjustment, both of which can be of concern in many liquid-in-liquid 3D printing methods. [19,21,25] In order for the reported printing approach to be used for applications such as fabrication of tissue mimics with various mechanical performances, it is necessary to investigate whether internal structure and mechanical properties of the prints can be tuned by varying the constituent components and conditions. Hence, different compositions of aqueous solution were prepared by controlling the amount of prepolymer and surface active molecules.…”

“…[1,[18][19][20] Successfully printed soft materials using the stated method include hydrogels, [18,21,22] cell-containing gels, [23] and PDMS elastomers. [19,24,25] The support baths are primarily composed of microparticle gels, [19,20,22,24] densely packed oil-inwater emulsions, [25] or polymer solutions. [26] In contrast, another variant of liquid-in-liquid 3D printing achieves printing and stabilization of all-liquid architectures by the formation of interfacial membranes [27] or by interfacial jamming of surface-active nanoparticles at the water-oil interface, [28,29] rather than through the use of support phase with specific rheological behavior.…”

Recent Progress in 3D Printing of Smart Structures: Classification, Challenges, and Trends

“…The modeling methods of self-repairing smart structures mainly include the use of self-repairing materials containing reversible bonds and the internal insertion of hollow vascular networks or capsules containing repairing compositions. Moreover, the introduction of 3D printing technology makes possible the manufacture of complicated self-healing structures, such as complex shapes of self-healing materials [11,[93][94][95][96][97][98] and complex internal vascular networks. [12,[99][100][101][102][103][104] The 3D printing of self-healing materials with reversible bonds is a common method of manufacturing self-healing smart structures.…”

“…Unfortunately, the photodegradability of methacrylate limits its application as a support material for 3D printing. Hu et al [93] developed a recyclable UV-resistant self-healing silicone oil-in-water emulsion glass material that provided a stable Electricity DIW Silicone elastomers Soft robotic face [81] Bucky gel N [79] Ag catalyst ink Microcircuit [82] Ag@CNF/PLA nanocomposite Multifunction and soft gripper [72] Carbon black particles and poly(ethylene glycol ethylene sulfide) oligomer N [84] Inkjet Elastomer based on acrylonitrilebutadiene rubber Bionic robotic [66] Tangoblack and Verowhite Bionic robotic [67] PμSL EAHs Soft robotics [16] e-3DP Two hydrogel-based inks (fugitive and catalytic).…”

“…They found that using the PμSL method of constructing microstructures on thin films improved perceptual sensitivity. They also fabricated high-sensitivity conformal piezoelectric sensors for the smart tactile-strain monitoring of robotic Reversible chemical bond DIW Silicone oil-in-water emulsion glass material Material itself N [93] κ-carrageenan/PAAm DN hydrogel 91 [94] Benzaldehyde-functionalized PHEMA with imine cross-links 98 [95] GH hydrogel 100 [97] DLP Polyurethane acrylate containing disulfide bonds 95 [11] PμSL Molecularly designed photoelastomer ink with thiol and disulfide groups 100 [98] FDM PLA þ Diels-Alder polymer 77 [96] Vascular network DIW Paraffin-based organic ink DCPD and Grubbs' catalyst particles 70 [25] 100 [100] 51 [101] 60 [102] FDM PVA PDMS 82 [99] PLA. 2120 Epoxy Cure agent and 2000 Epoxy Resin agent 28 [12] Sodium silicate 34 [104] a)…”