Chia‐Min Hsieh

Block copolymers (BCPs) offer distinct advantages for vat photopolymerization by enabling mechanically programmable network structures through microphase‐separated morphologies that can be kinetically trapped during curing, yielding properties unattainable in homogeneous resins. However, the respective roles of repeat‐unit sequence and solvent environment, together with their interplay in directing network formation and mechanical performance, remain unclear. Here, we synthesize a series of CO ₂ ‐based polycarbonate copolymers comprising a crosslinkable glassy poly(vinyl cyclohexene carbonate) (PVCHC, A block) and a non‐crosslinkable soft poly(propylene carbonate) (PPC, B block). The polymer sequence is systematically varied (ABA, BAB, and statistical), and solvent choice controls block‐selective swelling to jointly control gelation behavior, microphase morphology, and mechanical response through changes in the accessibility and local environment of photocrosslinkable vinyl groups during network formation, as revealed by photorheology and small angle x‐ray scattering. By tuning polymer sequence and curing solvent, we transform nominally identical formulations from brittle to highly ductile materials, achieving a three‐orders‐of‐magnitude range in toughness (0.003 to 9.1 MJ m ⁻³ ). These results establish clear structure–processing–property relationships and identify polymer sequence and selective solvation as powerful strategies for programming both printability and performance of block copolymer resins for additive manufacturing.

Block copolymers (BCPs) offer distinct advantages for vat photopolymerization by enabling mechanically programmable network structures through microphase‐separated morphologies that can be kinetically trapped during curing, yielding properties unattainable in homogeneous resins. However, the respective roles of repeat‐unit sequence and solvent environment, together with their interplay in directing network formation and mechanical performance, remain unclear. Here, we synthesize a series of CO ₂ ‐based polycarbonate copolymers comprising a crosslinkable glassy poly(vinyl cyclohexene carbonate) (PVCHC, A block) and a non‐crosslinkable soft poly(propylene carbonate) (PPC, B block). The polymer sequence is systematically varied (ABA, BAB, and statistical), and solvent choice controls block‐selective swelling to jointly control gelation behavior, microphase morphology, and mechanical response through changes in the accessibility and local environment of photocrosslinkable vinyl groups during network formation, as revealed by photorheology and small angle x‐ray scattering. By tuning polymer sequence and curing solvent, we transform nominally identical formulations from brittle to highly ductile materials, achieving a three‐orders‐of‐magnitude range in toughness (0.003 to 9.1 MJ m ⁻³ ). These results establish clear structure–processing–property relationships and identify polymer sequence and selective solvation as powerful strategies for programming both printability and performance of block copolymer resins for additive manufacturing.

The composition and architecture of CO₂-based aliphatic polycarbonates is revealed to impact DLP resin printability and bulk properties, offering significant prospects for advancing sustainable materials in 3D printing through polymer design.

3D printing is a versatile technology for creating objects with custom geometries and compositions and is increasingly employed for fabricating hybrid solid–liquid composites (SLCs). These composites, comprising solid matrices with integrated liquid components, showcase unique properties such as enhanced flexibility and improved thermal and electrical conductivities. This review focuses on methods to fabricate SLCs directly by different 3D printing techniques, e.g. without needing to backfill or impregnate a porous matrix. The techniques of extrusion, vat photopolymerization and material jetting combined with microfluidics, inkjet printing, vacuum filling and ultraviolet light curing to produce SLCs are emphasized. We also discuss the development of feedstocks, focusing on emulsions and polymer capsules as fillers, and analyze current literature to highlight their significance. The review culminates in a perspective on new directions, highlighting the potential of bicontinuous interfacially jammed emulsion gels (bijels) to facilitate the printing of continuous liquid pathways, alongside the importance of understanding ink formulation and stability. Concluding with future perspectives, we underline the transformative impact of 3D‐printed SLCs in diverse applications, signaling a significant advancement in the field. © 2024 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.

The rapid development of additive manufacturing, also known as three-dimensional (3D) printing, is driving innovations in both industry and academia. Direct ink writing (DIW), an extrusion-based 3D printing technology, can build 3D structures through the deposition of custom-made inks and produce devices with complex architectures, excellent mechanical properties, and enhanced functionalities. A paste-like ink is the key to successful printing. However, as new ink compositions have emerged, the rheological requirements of inks have not been well connected to printability, or the ability of a printed object to maintain its shape and support the weight of subsequent layers. In this review, we provide an overview of the rheological properties of successful DIW inks and propose a classification system based on ink composition. Factors influencing the rheology of different types of ink are discussed, and we propose a framework for describing ink printability using measures of rheology and print resolution. Furthermore, evolving techniques, including computational studies, high-throughput rheological measurements, machine learning, and materiomics, are discussed to illustrate the future directions of feedstock development for DIW. The goals of this review are to assess our current understanding of the relationship between rheological properties and printability, to point out specific challenges and opportunities for development, to provide guidelines to those interested in multi-material DIW, and to pave the way for more efficient, intelligent approaches for DIW ink development.