An Overview on 3D Printing of Structured Porous Materials and Their Applications

Abstract

Porous materials play an essential role in chemical processes such as catalysis, adsorption, and in emerging technologies for electronic materials, light harvesting, and energy transfer. By far, zeolites have contributed most to industrial development. Other porous solid such as activated carbon, metal–organic frameworks, covalent organic frameworks, and porous coordination polymers also have been studied by researchers in the past two decades. The use of porous solids is set to grow in the future, and so is the need to fabricate them into more complex and diverse geometries for a variety of applications. Additive manufacturing, also known as 3D printing, has provided the possibility to shape the materials into desired forms, which offers many advantages over their traditional configurations. Structured catalysts, for example, can help to overcome the drawbacks of conventional packed catalyst bed‐like mass or heat transfer limitations and high pressure drop. This review focuses on the latest advances as well as the current challenges in 3D printing of the porous solids. This article aims to contribute to the shape engineering of porous solids and provide a better understanding of their formulations, structures, techniques, properties, and applications.

In Situ Visualization of Polymerization-Induced Phase Separation for 3D-Printing of Porous Architectures

“…5,6 Different methods for the additive manufacturing of porous materials have been presented in recent years. 7 In short, there are three main categories: extrusion, photopolymerization and powder-based methods. In extrusion-based methods, slurries containing (structured) porous materials are deposited to form porous architectures.…”

“…In general, PIPS-based photopolymerization methods are the most versatile in terms of geometric freedom and still offer a wide range of materials with the lowest effort in postprocessing. 7 PIPS is most commonly used in the fabrication of porous thermoset materials, usually epoxy-based porous monoliths. 8−11 Here, it was found that the type and amount of porogenic solvents, as well as the monomer ratios and concentrations, play an important role in the pore structure obtained in the finished porous part.…”

“…In general, PIPS enables good control over the pore sizes and material properties. Unlike solvent-/nonsolvent-based phase separation (SIPS/NIPS), PIPS offers better opportunities to obtain narrow pore size distributions, no macrovoid formation, and good control over the pore structure by adjusting the resin composition. , Different methods for the additive manufacturing of porous materials have been presented in recent years . In short, there are three main categories: extrusion, photopolymerization and powder-based methods.…”

“…However, geometrically complex objects are difficult to produce since the residual powder still needs to be removed from the parts after the printing. In general, PIPS-based photopolymerization methods are the most versatile in terms of geometric freedom and still offer a wide range of materials with the lowest effort in postprocessing …”

Recent Advances in Visible Light Photoinitiating Systems Based on Flavonoids

“…Nowadays, tremendous efforts are devoted to developing highly efficient photoinitiating systems activable under visible light. Indeed, photopolymerization is used in a wide range of applications of photopolymerization from coatings and varnishes, adhesives, solvent-free paints and dental restoration materials to 3D/4D printing and microelectronics [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. If the reactivity of photoinitiators remains the main parameter governing the design of new structures, their toxicities and biocompatibilities are more and more regarded [16][17][18][19].…”