Viscoplastic Matrix Materials for Embedded 3D Printing

Abstract

Embedded three-dimensional (EMB3D) printing is an emerging technique that enables free-form fabrication of complex architectures. In this approach, a nozzle is translated omnidirectionally within a soft matrix that surrounds and supports the patterned material. To optimize print fidelity, we have investigated the effects of matrix viscoplasticity on the EMB3D printing process. Specifically, we determine how matrix composition, print path and speed, and nozzle diameter affect the yielded region within the matrix. By characterizing the velocity and strain fields and analyzing the dimensions of the yielded regions, we determine that scaling relationships based on the Oldroyd number, Od, exist between these dimensions and the rheological properties of the matrix materials and printing parameters. Finally, we use EMB3D printing to create complex architectures within an elastomeric silicone matrix. Our methods and findings will both facilitate future characterization of viscoplastic matrices and motivate the development of new materials for EMB3D printing.

Non‐Newtonian Polymer–Nanoparticle Hydrogels Enhance Cell Viability during Injection

“…An apparent yield stress of 30 Pa (Figure S1, Supporting Information) was measured at a rate of 1.45 Pa s −1 . While yield‐stress fluids are somewhat controversial, the apparent yielding of the material is observed in the solid–liquid transition of the hydrogels as they pass through the high shear zone in the needle followed by a liquid–solid transition after the hydrogel is ejected as shown in Figure 2 a . 1:5 HPMC:NP hydrogels were easily injectable yet maintained a solid‐like behavior after injection (Figure b).…”

Injectable supramolecular polymer–nanoparticle hydrogels enhance human mesenchymal stem cell delivery

“…36 The yield stress may also be characterized through plotting stress as a function of shear rate ( Figure S1). 36 The yield stress may also be characterized through plotting stress as a function of shear rate ( Figure S1).…”

Freeform, Reconfigurable Embedded Printing of All‐Aqueous 3D Architectures

“…[1,2,7,8,12,15,16,[23][24][25][26][27] The surrounding matrices that help to support the printed arbitrary 3D architectures include viscous oils, elastomers, self-healing hydrogels, and granular gel suspensions. [1,2,7,8,12,15,16,[23][24][25][26][27] The surrounding matrices that help to support the printed arbitrary 3D architectures include viscous oils, elastomers, self-healing hydrogels, and granular gel suspensions.…”

“…[23] If the ink viscosity is too low to suppress the interfacial tension effect, the printed threads break up www.advmat.de www.advancedsciencenews.com quickly. The formulated ATPS should allow the continuous writing of all-aqueous 3D structures and ensure a sufficient stabilization time against breakup until the interfacial membrane can be formed.…”

“…The formulated ATPS should allow the continuous writing of all-aqueous 3D structures and ensure a sufficient stabilization time against breakup until the interfacial membrane can be formed. [23,46] Indeed, by taking these principles into consideration, for PAA-DEX/PEO-2m system, we optimize that the ink phase is composed of 3 wt% PAA and 0.05 wt% fluorescein isothiocyanate (FITC)-DEX while the matrix phase consists 5 wt% PEO-2m. [23] If the ink viscosity is too low to suppress the interfacial tension effect, the printed threads break up www.advmat.de www.advancedsciencenews.com quickly.…”