3D Printing of Hierarchical Porous Ceramics for Thermal Insulation and Evaporative Cooling

Abstract

Materials for thermal management of buildings offer an attractive approach to reduce energy demands and carbon emissions in the infrastructure sector, but many of the state‐of‐the‐art insulators are still expensive, flammable, or difficult to recycle. Here, a 3D printing process is developed and studied to create hierarchical porous ceramics for thermal insulation and passive cooling using recyclable and widely available clay as raw material. Inks comprising particle‐stabilized foams are employed as a template for the generation of the hierarchical porosity. Using foams with optimized rheological properties, the printing parameters and sintering conditions required for the manufacturing of hierarchical porous ceramics via Direct Ink Writing are established. The sintering temperature is found to strongly affect the size distribution of micropores, thus controlling the mechanical, thermal, and evaporative cooling properties of sintered printed structures. By combining suspension‐ and foam‐based inks in a multimaterial printing approach, inexpensive and recyclable clay‐based bricks are manufactured with structural, thermal insulating, and passive cooling capabilities.

A bioinspired surface tension-driven route toward programmed cellular ceramics

“…In conventional direct 3D printing process, starting with ceramic powder (powder sintering-based SLS) or its composite with additive polymer (slurry extrusion-based DIW or photosensitive resin-based SLA/DLP), structure building and component assembly are conducted in one step, which inevitably causes problems, such as the complex feedstock preparation (e.g., complicated surface modification process to achieve a uniform distribution when mixing ceramic powder with resin in DIW and SLA/DLP), the limited ceramic constituent loading (usually less than 50 vol% for SLA/DLP), the reduced printing accuracy and speed (e.g., twice the exposure time per layer when printing ceramic-resin composites compared with common resin in DLP), and the increasing processing cost (excessive energy consumption in SLS). Supplementary Table 1 summarizes the parameters in terms of effective constituent loading, fabrication speed, and accessible feature size for the well-established DIW, SLA/DLP, and SLS 34 – 45 . The slurry extrusion-based DIW has the advantage of high effective constituent loading regardless of its limited fabrication speed and feature size, while the photosensitive resin-based SLA/DLP possesses an increasing fabrication speed and decreasing feature size, with limited effective constituent loading.…”

Dual carbon sequestration with photosynthetic living materials

“…Implementing photosynthetic living materials in broad application still requires improved usability and upscaling of the material production. This can be achieved by taken advantage of recent advances in biofabrication for the creation of larger scale porous 62 or granular 63 structures. In addition, methods to engineer optical structures at scale for efficient light harnessing, may further improve efficiency 49 .…”

Robotic 3D Printing of Geopolymer Foam for Lightweight and Insulating Building Elements

“…For example, clay-based foams sintered for consolidation were used with F3DP in another study to produce hierarchical porous ceramic bricks with programmed thermal insulation and evaporative cooling effects. 14 Sintered mineral foams were utilized with F3DP to show their potential combined with concrete for facade and beam structures. 15 The energy-intensive sintering step could be omitted using set-on-demand geopolymer-hardened mineral foam to 3D print the functional stay-in-place formwork of a ribbed concrete slab prototype.…”