Functional Nanoclay Suspension for Printing-Then-Solidification of Liquid Materials

Abstract

Additive manufacturing (AM) enables the freeform fabrication of complex structures from various build materials. The objective of this study is to develop a novel Laponite nanoclay-enabled "printing-then-solidification" additive manufacturing approach to extrude complex three-dimensional (3D) structures made of various liquid build materials. Laponite, a member of the smectite mineral family, is investigated to serve as a yield-stress support bath material for the extrusion printing of liquid build materials. Using the printing-then-solidification approach, the printed structure remains liquid and retains its shape with the help of the Laponite support bath. Then the completed liquid structures are solidified in situ by applying suitable cross-linking mechanisms. Finally, the solidified structures are harvested from the Laponite nanoclay support bath for any further processing as needed. Due to its chemical and physical stability, liquid build materials with different solidification/curing/gelation mechanisms can be fabricated in the Laponite bath using the printing-then-solidification approach. The feasibility of the proposed Laponite-enabled printing-then-solidification approach is demonstrated by fabricating several complicated structures made of various liquid build materials, including alginate with ionic cross-linking, gelatin with thermal cross-linking, and SU-8 with photo-cross-linking. During gelatin structure printing, living cells are included and the postfabrication cell viability is above 90%.

Study of extrudability and standoff distance effect during nanoclay-enabled direct printing

“…As a result, the NIPAAm solution has poor extrudability and cannot be used alone for extrusion-based printing applications. Figure 3b-1 and b-2 shows the extrusion process of the Laponite nanoclay suspension, a Bingham plastic material with the unique yield-stress property [12,13,25,26] a nozzle, the Laponite nanoclay suspension in the nozzle is sheared and behaves as a shear thinning fluid material. If the applied stress is higher than its shear yield stress, it behaves like liquid; otherwise, it behaves like solid.…”

Support Structures for Additive Manufacturing: A Review

“…This bulk support material could successfully support every feature of a printed part when the yield stress of the support material is higher than surface tension and gravitational forces. Then, the whole liquid structure is solidified in situ by applying suitable cross-linking mechanisms [74,75]. Hinton et al [76] demonstrated a new method of 3D printing polydimethylsiloxane (PDMS) using a hydrophilic Carbopol support bath.…”

Recent Advances in Enabling Technologies in 3D Printing for Precision Medicine

“…Embedded printing techniques overcome challenges in traditional printing methods by utilizing self‐healing materials as support baths (Table ). These fabrication techniques, compatible with a range of bioprinting platforms, also increase material compatibility of extrusion fabrication systems and enhance the resolution and complexity of fabricated constructs . Generally, the approach involves the extrusion of one material into the support bath, stabilization of the material (either the printed material or support), and then washing of the unstable material.…”