Ultrafast Stiffening of Concentrated Thermoresponsive Mineral Suspensions


Extrusion-based 3D printing with rapidly hardening polymeric materials is capable of building almost any conceivable structure. However, concrete, one of the most widely used materials for large-scale structural components, is generally based on inorganic binder materials like Portland cement. Unlike polymeric materials, a lack of precise control of the extent and rate of solidification of cement-based suspensions is a major issue that affects the ability to 3D-print geometrically complex structures. Here, we demonstrate a novel method for controllable-rapid solidification of concentrated mineral suspensions that contain a polymer binder system based on epoxy and thiol precursors as well as one or more mineral fillers like quartz and calcite. The thermally triggered epoxy-thiol condensation polymerization induces rapid stiffening of the hybrid suspensions (0.30 ≤ φ ≤ 0.60), at trigger temperatures ranging between 50 °C and 90 °C achieving average stiffening rates up to 400 Pa/s. The use of nucleophilic initiators such as 1-methylimidazole provides control over the activation temperature and curing rate, thereby helping to achieve an adjustable induction period and excellent thermal latency. By using multiple techniques, we provide guidelines to create designer compositions of mineral suspensions that utilize thermal triggers to achieve thermal latency and ultrafast stiffening - prerequisite attributes for 3D-manufacturing of topologically-optimized structural components.


Materials Science and Engineering


The authors acknowledge the partial financial support for this research provided by the U.S. National Science Foundation (DMREF: 1922167), TRANSCEND, a joint UCLA-NIST Consortium that is funded by its industry and agency partners, Bavaria-California Technology Center (BaCaTec), The Advanced Research Projects Agency-Energy (ARPA-e: DE-AR-0001147), and the 3DConcrete Printing Network for Accelerating Progress in Concrete Additive Manufacturing supported by the U.S. National Science Foundation (AccelNet OISE: 2020095).

Keywords and Phrases

3D Printing; Additive Manufacturing; Epoxy-Thiol Polycondensation; Stimuli-Responsive Suspensions; Thermoresponsive Suspensions; Ultrafast Stiffening

International Standard Serial Number (ISSN)

1873-4197; 0264-1275

Document Type

Article - Journal

Document Version


File Type





© 2022 Elsevier, All rights reserved.

Publication Date

01 Sep 2022