Vat Photopolymerization Processes Research Articles

Measuring and Simulating the Transient Packing Density During Ultrasound Directed Self‐Assembly and Vat Polymerization Manufacturing of Engineered Materials

AbstractUltrasound‐directed self‐assembly (DSA) uses ultrasound waves to organize and orient particles dispersed in a fluid medium into specific patterns. Combining ultrasound DSA with vat photopolymerization (VP) enables manufacturing materials layer‐by‐layer, wherein each layer the organization and orientation of particles in the photopolymer is controlled, which enables tailoring the properties of the resulting composite materials. However, the particle packing density changes with time and location as particles organize into specific patterns. Hence, relating the ultrasound DSA process parameters to the transient local particle packing density is important to tailor the properties of the composite material, and to determine the maximum speed of the layer‐by‐layer VP process. This paper theoretically derives and experimentally validates a 3D ultrasound DSA model and evaluates the local particle packing density at locations where particles assemble as a function of time and ultrasound DSA process parameters. The particle packing density increases with increasing particle volume fraction, decreasing particle size, and decreasing fluid medium viscosity is determined. Increasing the particle size and decreasing the fluid medium viscosity decreases the time to reach steady‐state. This work contributes to using ultrasound DSA and VP as a materials manufacturing process.

High pressure salt water and low temperature effects on the material performance characteristics of additive manufacturing polymers

The effects of salt water exposure at deep ocean depth pressures when coupled with low temperatures on the material characteristics of three unique additively manufactured polymers has been investigated through a detailed experimental approach. The polymers in the study were manufactured utilizing both Vat Photopolymerization and Material Extrusion printing techniques. The Material Extrusion process was utilized to produce material specimens of Stratasys ULTEM 9085 and Markforged Onyx while the Vat Photopolymerization process was used to produce specimens of Accura ClearVue. The ULTEM 9085 and Markforged Onyx are filament based polymers and the ClearVue is a liquid based resin. The specimens were first submerged in a high pressure, salt water bath of 3.5% NaCl solution at 34.5 MPa (5000 lb/in2) for a total exposure time of 60 days to determine the water absorption characteristics. Subsequent to the salt water exposure at high pressure, the specimens were evaluated to determine changes in tension, compression, flexure, and in-plane fracture properties. To determine the effects of water saturation and low temperature coupling, the mechanical testing was performed at temperatures of 20 °C, 0 °C and −20 °C in both dry and saturated conditions. Additionally, non-destructive testing in the form of TeraHertz and FIRT imaging was conducted to analyze the physical material changes through the thickness of the material due to the saline water absorption. To quantify the change in material storage and loss moduli properties, Dynamic Mechanical Analysis (DMA) characterization was performed on each of the AM polymers in dry and saturated states. The DMA testing also quantified changes in the Glass Transition Temperature because of salt water exposure. In summary, The current study investigates the effects of coupled long term/high pressure salt water exposure with low temperatures on the mechanical and material characteristics of three unique AM polymers by: (1) immersing the materials in a salt water solution at 34.5 MPa for 60 days, (2) Conducting post exposure mechanical testing on the materials at 0 °C and −20 °C with comparisons to 20 °C testing on dry specimens, and quantifies changes in material properties through DMA experiments. The results from all testing in the study show that high pressure salt water exposure when coupled with low temperatures has unique effects on each of the materials considered in the study and careful consideration to each parameter must be given based on the material type when components will be employed in marine operations.

Incorporating boron carbide into fused silica imparts multiple mechanisms to facilitate vat photopolymerization

Rapid manufacturing of complex-shaped ceramic components has long been a pressing issue in the aerospace industry. Recent progress in this direction takes advantage of additive manufacturing, by employing vat photopolymerization (VPP) followed by sintering. Here we demonstrate a new recipe/protocol that enables the VPP route to deliver silica products of high relative density as well as high strength. This is achieved by incorporating 2.5 wt% of boron carbide (B4C) into the fused silica slurry, which offers beneficial effects in multiple fronts. During the VPP process, the added black B4C, together with the refractive index difference between the two components in the mixture, effectively increased the light absorbance. Upon sintering, the boron oxide produced by the oxidation of B4C played the role of a sintering aid. The boron oxide also helped to suppress the crystallization of the amorphous silica and therefore the formation of cracks. As a result, the overall quality (forming precision, density, strength and dielectric constant) of the product surpasses by far those prepared previously via VPP-sintering. In particular, the flexural strength reached 60.7 MPa, a factor of 2.5 better than the previously reported highest value. Extending the success above further, we have manufactured a complex-structured silica radome, as a demonstration of the high-quality products achievable for practical applications.

A vat photopolymerization process for structures reinforced with spatially steered flexible fibers

We present a modified vat photopolymerization process for realizing novel fiber-reinforced composite parts wherein continuous fibers are selectively positioned and oriented across multiple layers along the build direction. This is in contrast to laminates and fiber-wound parts made by repeating fiber patterns; and additively manufactured parts with fibers inserted a posteriori or co-extruded selectively. Our process endows two benefits to the parts made with it: (i) spatially steered fibers embedded along specific paths inside to increase stiffness and strength; and (ii) in-situ fiber-matrix interface concurrently cured with matrix material as opposed to the matrix-matrix interface that exists in co-extruded fibers. The process is enabled by a robot manipulator that guides the fiber in each layer by incrementally orienting it along the tangential direction to the bespoke path. The robot arm and the end-effector do not obstruct the UV light source as they pull the fiber taut from afar in multiple directions to alleviate the undesirable effects of shadows. The robot arm is integrated with the build platform and the UV projector, and the entire process is automated. Examples that illustrate making parts with single and multiple fibers are presented to show the efficacy of the process and the machine. An example is shown with continuous fibers embedded along a few spatially varying principal-stress-flow paths inside a part to improve its stiffness and strength. An increase of 71 % in stiffness and 90 % in strength of the part is observed at fiber volume fraction as small as 0.39 %.

Viscosity of Mono‐ and Polydisperse Mixtures of Photopolymer and Rigid Spheres for Manufacturing of Engineered Composite Materials Using Vat Photopolymerization

Vat photopolymerization (VP) additive manufacturing involves selectively curing low‐viscosity photopolymers via exposure to ultraviolet light in a layer‐wise fashion. Dispersing filler materials in the photopolymer enables tailored end‐use properties, but also increases the viscosity and the timescale associated with interparticle network structural recovery postshear. These rheological properties influence self‐leveling and recoating of the liquid photopolymer mixture during VP. Herein, viscosity of photopolymer and rigid spherical glass microparticles (filler) is experimentally determined as a function of filler fraction, filler size distribution (mono‐ and polydisperse), shear rate, and temperature, which are important VP process parameters. Employing existing viscosity models for mono‐ and polydisperse polymer mixtures demonstrates that particle–particle interactions and the formation of nonspherical clusters of particles strongly affect the viscosity of both monodisperse and polydisperse mixtures with particle volume fractions > 0.05 due to agglomeration/deagglomeration of clusters at elevated shear rates. Consequently, unmodified viscosity models, which assume uniformly dispersed, rigid, spherical particles, are applicable only for mixtures with particle volume fractions < 0.05. It is shown that modifying model parameters such as the fluidity limit and intrinsic viscosity, which explicitly account for nonspherical clusters of particles, improves agreement between viscosity models and experiments, in particular when using a fractal approach.

Experimental and numerical investigation on novel three-dimensional printed bio-inspired hexagonal lattices for energy absorption and stiffness behavior

In the current study, a new type of novel lattice structures with the concept of bio-mimicking three different nature-inspired designs from the honeycomb patterns, the overlapping phenomenon of the scales present on fish dermal layers, and scutes pattern observed from the top skin layers present on crocodile species are developed. These lattice structures are designed within a cubic volume of 30 mm. The design of lattice unit cells is made with two different geometrical sizes of 4 and 6 mm with different overlapping areas of 20, 30, 40, and 50% calculated from each cell area. All the unit cells’ walls are maintained at 0.4 and 0.6 mm only. The specimens are modeled and manufactured through the VAT photopolymerization process, one of the significant additive manufacturing principles for great dimensional accuracy with negligible defects in 3D printing (3DP). The research approach used to develop lightweight bio-inspired structures has been laid out, starting with observing design that served as inspiration. The cured 3D-printed specimens are examined under quasi-static compressive loading carried out on all specimens as per ASTM 1621 standards to measure the crashworthiness response of designed specimens. The energy ingestion capacity of all the specimens is assessed. A good correlation is observed between the experimental and numerical results for better validation. The best design parameters among all 16 specimens are identified for applying energy absorption applications in the automobile and aviation fields in real-time.

Vat photopolymerization additive manufacturing process modeling: a thermal-chemical coupling approach informed by in-situ and ex-situ characterization data

Vat photopolymerization (VPP) is one of the most widely used additive manufacturing methods. The VPP process temperature and material curing reaction interplay with each other to critically determine the final product quality. Insights about the time-varying process temperature and degree of conversion (DoC) is desired for VPP process control but difficult to attain due to lacking effective operando characterization technologies. This work reports a new method to create a thermal-chemical model of the VPP process by solving an inverse heat conduction problem (IHCP) based on in-situ observable temperature measurement to estimate the chemistry reaction-induced heat source that is a function of DoC. Ex-situ photo differential scanning calorimetry (Photo-DSC) characterization is used to initialize the chemistry reaction model parameters so that DoC can be calculated. Specifically, vat substrate temperature is measured using an in-situ infrared thermal camera and used as input to solve an IHCP for estimating exothermic heat generation rate for the internal heat generation component at the curing part. Overall, the newly developed VPP modeling framework combines an IHCP that is optimized by in-situ thermal monitoring with a chemical reaction heat generation and conduction model that is educated by Photo-DSC characterization. The model predictions of temperature and DoC are experimentally validated by comparing against in-situ temperature measurement and ex-situ spectroscopy measurement of prints at different exposure times.

Engineered Living Material Bioreactors with Tunable Mechanical Properties using Vat Photopolymerization.

3D-printed engineered living materials (ELM) are promising bioproduction platforms for agriculture, biotechnology, sustainable energy, and green technology applications. However, the design of these platforms faces several challenges, such as the processability of these materials into complex form factors and control over their mechanical properties. Herein, ELM are presented as 3D-printed bioreactors with arbitrary shape geometries and tunable mechanical properties (moduli and toughness). Poly(ethylene glycol) diacrylate (PEGDA) is used as the precursor to create polymer networks that encapsulate the microorganisms during the vat photopolymerization process. A major limitation of PEGDA networks is their propensity to swell and fracture when submerged in water. The authors overcame this issue by adding glycerol to the resin formulation to 3D print mechanically tough ELM hydrogels. While polymer concentration affects the modulus and reduces bioproduction, ELM bioreactors still maintain their metabolic activity regardless of polymer concentration. These ELM bioreactors have the potential to be used in different applications for sustainable architecture, food production, and biomedical devices that require different mechanical properties from soft to stiff.

Study of Proximity Effect in Projection based Micro Vat Photopolymerization Process

Micro Projection-based Stereolithography (µPSL), also known as micro vat photopolymerization, is a promising technology that could revolutionize microfabrication by providing benefits similar to traditional lithography while reducing production time and cost. However, it faces a significant challenge in the form of the "proximity effect." This effect occurs when adjacent features are too close together, causing undesirable artifacts and limiting the achievable fabrication resolution. The proximity effect is caused by interactions between adjacent pixels of light and affects both the spatial and temporal domains of the fabrication process. Although researchers have been aware of this issue for some time, there has been little progress in understanding and addressing the proximity effect in micro vat photopolymerization. Existing models developed for laser-based systems can explain the effect to some extent, but they do not fully account for the impact of large area projection or explain how local threshold changes affect part size. This research aims to fill this knowledge gap by using in-situ observation systems to experimentally study the spatial and temporal proximity effects in single-shot vat photopolymerization microfabrication. We also investigate the role of oxygen in the proximity effect and lay the groundwork for better understanding how the effect impacts periodic structures with micronic inter-feature distances. In conclusion, while micro vat photopolymerization offers significant advantages over traditional lithography, the proximity effect remains a significant obstacle. This research represents an important step forward in addressing this challenge and improving the accuracy and resolution of vat photopolymerization in microfabrication.

Fabrication of 3D-printed molds for polydimethylsiloxane-based microfluidic devices using a liquid crystal display-based vat photopolymerization process: printing quality, drug response and 3D invasion cell culture assays

Microfluidic platforms enable more precise control of biological stimuli and environment dimensionality than conventional macroscale cell-based assays; however, long fabrication times and high-cost specialized equipment limit the widespread adoption of microfluidic technologies. Recent improvements in vat photopolymerization three-dimensional (3D) printing technologies such as liquid crystal display (LCD) printing offer rapid prototyping and a cost-effective solution to microfluidic fabrication. Limited information is available about how 3D printing parameters and resin cytocompatibility impact the performance of 3D-printed molds for the fabrication of polydimethylsiloxane (PDMS)-based microfluidic platforms for cellular studies. Using a low-cost, commercially available LCD-based 3D printer, we assessed the cytocompatibility of several resins, optimized fabrication parameters, and characterized the minimum feature size. We evaluated the response to both cytotoxic chemotherapy and targeted kinase therapies in microfluidic devices fabricated using our 3D-printed molds and demonstrated the establishment of flow-based concentration gradients. Furthermore, we monitored real-time cancer cell and fibroblast migration in a 3D matrix environment that was dependent on environmental signals. These results demonstrate how vat photopolymerization LCD-based fabrication can accelerate the prototyping of microfluidic platforms with increased accessibility and resolution for PDMS-based cell culture assays.

Towards 3D-printed alumina-based multi-material components with enhanced thermal shock resistance

A novel architectural design is introduced which utilizes the layer-by-layer capabilities of the vat photopolymerization 3D printing process to fabricate multi-material ceramic components with improved thermal shock resistance. The combination of 3D-printed alumina-zirconia (ZTA) with alumina (A) layers generates compressive residual stresses in the embedded alumina regions during cooling down from sintering. Thermal shock tests in water are performed on samples at different maximum temperatures and the strength degradation of the multi-material design is investigated and compared to the reference monoliths. Experimental results show that the retained strength of the multi-material ceramic after thermal shock is twice as high as that of the monoliths, associated with the crack arrest capability of the embedded layers. The concept is demonstrated on 3D-printed multi-ceramic blades for potential high temperature applications, showing enhanced “damage-tolerance” against thermal shock cracks. These findings open the path for fabricating reliable ceramic components using the vat photopolymerization process.

A Comprehensive Mechanical Examination of ABS and ABS-like Polymers Additively Manufactured by Material Extrusion and Vat Photopolymerization Processes.

Additive manufacturing technologies have developed rapidly in recent decades, pushing the limits of known manufacturing processes. The need to study the properties of the different materials used for these processes comprehensively and in detail has become a primary goal in order to get the best out of the manufacturing itself. The widely used thermoplastic polymer material acrylonitrile butadiene styrene (ABS) was selected in the form of both filaments and ABS-like resins to investigate and compare the mechanical properties through a series of different tests. ABS-like resin material is commercially available, but it is not a sufficiently mechanically studied form of the material, which leads to the rather limited literature. Considering that ABS resin is a declared material that behaves like the ABS filament but in a different form, the objective of this study was to compare these two commercially available materials printed with three different 3D printers, namely Fused Deposition Modelling (FDM), Stereolithography (SLA) and Digital Light Processing (DLP). A total of 45 test specimens with geometries and test protocols conforming to the relevant standards were subjected to a series of tensile, three-point bending and compression tests to determine their mechanical properties. Characterization also included evaluation of morphology with 2D and 3D microscopy, dimensional accuracy of 3D scans, and Shore A hardness of each material and 3D printing process. Tensile testing results have shown that FDM toughness is 40% of the value for DLP. FDM elongation at break is 37% of DLP, while ultimate tensile stress for SLA is 27% higher than FDM value. Elastic modulus for FDM and SLA coincide. Flexure testing results indicate that value of DLP flexural modulus is 54% of the FDM value. SLA strain value is 59% of FDM, and DLP ultimate flexure stress is 77% of the value for FDM. Compression test results imply that FDM specimens absorb at least twice as much energy as vat polymerized specimens. Strain at break for SLA is 72% and strain at ultimate stress is 60% of FDM values. FDM yield stress is 32% higher than DLP value. SLA ultimate compressive stress is half of FDM, while value for DLP compressive modulus is 69% of the FDM value. The results obtained are beneficial and give a more comprehensive picture of the behavior of the ABS polymers used in different forms and different AM processes.

Tensile properties and sustainability assessment of vat photopolymerization 3D printed components with recovered plastic filler

AbstractRaw material production represents one of the major issues of additive manufacturing as it can be an expensive and environmentally impactful phase. One example is provided by the light-curing resins used in vat photopolymerization processes. To this purpose, this study aims at evaluating the use of recovered polyamide powders as filler for photocurable resins from different perspectives; to this purpose, tensile tests were performed in order to evaluate the effect of recovered powder content as filler on the mechanical properties of the resin. Furthermore, a scanning electron microscopy and computed tomography analyses were carried out to investigate the fracture mechanisms and dispersion of the filler within the resin. Finally, a life cycle assessment analysis was performed to evaluate the effect of different reused power contents as filler on the environmental impact of 3D printed components. Results showed that the use of recovered powder as filler for light-curing resin in vat photopolymerization 3D printing parts allows the obtaining of an improvement in terms of tensile strength and elastic modulus up to 62% and 107%, respectively. In addition, a reduction in environmental impacts up to 48% was obtained. A homogeneous dispersion of the particles within the resin was observed at the different filler contents investigated.

Effect of glass fiber reinforcement on compressive strength of photopolymer composite fabricated using vat‐photopolymerization additive technique: An experimental and modeling approach

AbstractShort or nanofillers‐reinforced composites increase the thermo‐mechanical characteristics of additive manufacturing (AM) base materials. Effective outputs were regulated via parametric optimisation and custom production. One of the most used AM method, Vat photopolymerization (VPP), creates complex and geometrically precise photopolymer parts. This study prepares photopolymer composite (PPC) samples with 2.0, 4.0, 6.0, and 8.0 volume percentages of short glass fiber (SGF) using an inter‐stage stirring method in DLP‐based VPP process. An adequate curing time and formable layer thickness were evaluated for the printability performance of SGF‐photopolymer composite. The 4.0% PPC‐sample showed a 20% higher compressive yield strength than pure photopolymer and other volume fractions. The consequences of increased strength values were assessed by the effect of stirring method and the fractography analysis of PPC specimen. The investigation additionally encompassed numerical simulations that employed an innovative technique for constructing and simulating three‐dimensional representative volume elements (RVEs). The RVEs were designed to replicate the experimental outcomes by randomly situating and orienting fillers within the matrix. The study employs the calibrated Three Network (TN) viscoplastic constitutive material model as the matrix property, and the simulation results demonstrate a margin of error of 5%–10% when compared to the experimental findings.Highlights Layer‐wise availability of SGFs through inter‐stage stirring method The exposure time and layer thickness were determined by Jacob's working curve Concept of RVE is used to combine individual SGF layers into a single layer SEM showed that increasing SGF layer resists cracking better than neat matrix Experimental data and numerical simulations are in good agreement

Rapid vat photopolymerization through a superamphiphobic interface

ABSTRACT Vat photopolymerization (VPP) is one of the convenient methods to create high-precision parts; however, due to the significant adhesion between the cured layer of the photopolymer resin and the release film, the currently prevalent VPP equipment is less productive and thus challenging in achieving production on a large scale. To tackle the issues above, a facile method is utilised to produce a transparent film capable of effectively resisting the photopolymer resin. Such film is achieved by incorporating micron-nanometre layered rough features and low surface energy materials onto the surface of quartz glass. It allows innovative applications in speedy VPP processes, achieving a printing speed of up to 323 mm/h in an LCD (Liquid Crystal Display) 3D printer while maintaining sound accuracy, exceptional durability and fair applicability, thanks to the features of the prepared film. The presented approach provides new perspectives into the production and application of VPP technology.

Effect of the cellulose nanofiber on ultraviolet curable resin for additive manufacturing: Mechanical properties and printability

Cellulose nanofiber incorporated into vat photopolymerization technology has garnered significant attention as an eco-friendly reinforcement owing to its high mechanical properties and biocompatibility. However, several notable challenges still remain, particularly concerning the feasibility of handling complex geometries. In this study, we present a vat photopolymerization resin enhanced with CNF. To assess printability on a standard 3D printer, various formulations were created by adjusting the CNF content, and their rheological properties were measured. Subsequently, specimens with different constraints were prepared to evaluate the impact of CNF content on printability. The mechanical properties of the 3D printed composites were assessed using tensile/flexural tests and morphology analysis was conducted by using micro-CT and scanning electron microscope. The findings revealed that a 0.5 wt% CNF-reinforced resin successfully produced intricate geometries with exceptional mechanical strength. These results underscore the importance of determining an optimal reinforcement content to ensure both printability and desirable mechanical properties. Furthermore, this study serves as inspiration for incorporating other fibers into vat photopolymerization processes.

3D Printing of Gel Polymer Electrolytes for Sodium-Ion Batteries

In order to maximize the capabilities of existing battery chemistries, a big effort has been recently focused on manufacturing more complex battery structures, which promotes 3D lithium ion diffusion resulting in an increase in power density.1-3 The current limitation is still the manufacturing part, which is often complex and expensive for mainstream production. 3D printing appears in this context as an exceptional tool to fill the gaps for 3D battery manufacturing. Among the 3D printing processes, vat photopolymerization is especially interesting thanks to its high printing resolution through a layer-by-layer curing approach that solidifies a UV-photocurable resin. Multiple examples of functional 3D printed batteries manufactured by various methods have been reported in the literature.4-7 Most of the recent works have been focused on half-cells where only one electrode is printed, or complete cells containing printed electrodes but using a non-printed conventional separator-electrolyte couple in between. Among the alternatives to replace this couple for a functional and printable material, gel polymer electrolytes appear as an appropriate option because they possess the advantages of a liquid electrolyte, without severely compromising the mechanical integrity. In addition, they exhibit competitive ionic conductivity and enhanced safety in comparison to liquid electrolytes, and they do not require a thermal post-processing step to be manufactured. Combining the knowledge in this topic with the design freedom that 3D printing allows will certainly contribute to obtaining the next generation of 3D printed batteries. In a first instance, this work will show a brief overview about suitable UV-photocurable resin compositions that can be employed as gel polymer electrolytes in sodium-ion batteries, with a view to employ them as material feedstock in the high-resolution vat photopolymerization process. The freedom of design that 3D printing allows will be then shown through a variety of printed items that transcend the well-known tape casting method to produce conventional gel polymer electrolytes. Finally, a variety of electrochemical tests to prove stability, ionic conductivity and performance within sodium-ion batteries will be shown. Talin, A. A. et al. Fabrication, Testing, and Simulation of All-Solid-State Three-Dimensional Li-Ion Batteries. ACS Appl. Mater. Interfaces 8, 32385–32391 (2016).Liu, Y. et al. Transforming from planar to three-dimensional lithium with flowable interphase for solid lithium metal batteries. Sci Adv 3, eaao0713 (2017).Long, J. W., Dunn, B., Rolison, D. R. & White, H. S. 3D architectures for batteries and electrodes. Adv. Energy Mater. 10, 2002457 (2020).Cheng, M., Deivanayagam, R. & Shahbazian-Yassar, R. 3D printing of electrochemical energy storage devices: A review of printing techniques and electrode/electrolyte architectures. Batter. supercaps 3, 130–146 (2020).Pang, Y. et al. Additive manufacturing of batteries. Adv. Funct. Mater. 30, 1906244 (2020).Zeng, L. et al. Recent progresses of 3D printing technologies for structural energy storage devices. Materials Today Nano 12, 100094 (2020).Maurel, A. et al. Toward High Resolution 3D Printing of Shape-Conformable Batteries via Vat Photopolymerization: Review and Perspective. IEEE Access 9, 140654–140666 (2021).

3D Printing of Batteries from Lunar and Martian Regolith

To maximize the sustainability of future space missions, the utilization of local resources available on the Moon or Mars, also known as in-situ resource utilization (ISRU), is crucial to develop infrastructures such as habitation modules, power generation, and energy storage facilities.1–3 This work presents a perspective aiming to introduce the future of batteries manufacturing on the lunar and martian environment from ISRU materials. Based on the composition of the lunar and martian soil,4–7 the choice of the battery technology and materials for the different battery components (electrodes, electrolyte, current collectors and packaging) are examined. The motivations for selecting additive manufacturing technologies as a unique approach to support human operations in space, on the surface of the Moon or Mars, and any other locations where cargo resupply is not as readily available, as well as the need for high resolution multi-material printing methods, are discussed. Additive manufacturing paves the way to three-dimensional rechargeable battery architectures with enhanced specific surface area, three-dimensional ion diffusion, and improved power performances, while also allowing the development of shape-conformable batteries to maximize the energy storage within the final application.8–15 The in-space additive manufacturing process of shape-conformable batteries using in-situ resources is in direct alignment with the NASA’s objectives to demonstrate in-space autonomous manufacturing and assembly of complete systems by 2030, and to enable Humans survival, explore deep space, and visit planetary surfaces by 2040.16 Such initiatives also contribute to reducing power-related payload weight and volume in future missions, thus reducing the risk for long term Moon or even Mars missions where rapid resupply will be logistically infeasible. In this context, this presentation will provide a perspective of what is required to 3D print batteries on lunar and martian surfaces,17 an overview of our ongoing project dedicated to AM of sodium-ion batteries from resources available on the Moon and Mars and our recent work on 3D printing of TiO2 negative electrode material by means of the vat photopolymerization process.18 (1) Anand, M. et al. A Brief Review of Chemical and Mineralogical Resources on the Moon and Likely Initial in Situ Resource Utilization (ISRU) Applications. Planet. Space Sci. 2012, 74 (1), 42–48.(2) Edmunson. Building a Sustainable Human Presence on the Moon and Mars. New Horizons Summit.(3) McMillon-Brown, L. et al. What Would It Take to Manufacture Perovskite Solar Cells in Space? ACS Energy Lett. 2022, 7 (3), 1040–1042.(4) Heiken, G. et al. Lunar Sourcebook: A User’s Guide to the Moon; CUP Archive, 1991.(5) Dreibus, G. et al. Lithium and Halogens in Lunar Samples. Philos. Trans. R. Soc. Lond. A 1977, 285 (1327), 49–54.(6) Taylor, G. J. The Bulk Composition of Mars. Geochem. Explor. Environ. Analy. 2013, 73 (4), 401–420.(7) Yoshizaki, T. et al. The Composition of Mars. Geochim. Cosmochim. Acta 2020, 273, 137–162.(8) Maurel, A. et al. Highly Loaded Graphite-Polylactic Acid Composite-Based Filaments for Lithium-Ion Battery Three-Dimensional Printing. Chem. Mater. 2018, 30 (21), 7484–7493.(9) Maurel, A. et al. Considering Lithium-Ion Battery 3D-Printing via Thermoplastic Material Extrusion and Polymer Powder Bed Fusion. Additive Manufacturing 2020, 101651.(10) Martinez, A. C. et al. Additive Manufacturing of LiNi1/3Mn1/3Co1/3O2 Battery Electrode Material via Vat Photopolymerization Precursor Approach. Sci. Rep. 2022, 12 (1), 1–13.(11) Maurel, A. et al. Overview on Lithium-Ion Battery 3D-Printing By Means of Material Extrusion. ECS Trans. 2020, 98 (13), 3–21.(12) Maurel, A. et al. Toward High Resolution 3D Printing of Shape-Conformable Batteries via Vat Photopolymerization: Review and Perspective. IEEE Access 2021, 9, 140654–140666.(13) Maurel, A. et al. Ag-Coated Cu/Polylactic Acid Composite Filament for Lithium and Sodium-Ion Battery Current Collector Three-Dimensional Printing via Thermoplastic Material Extrusion. Frontiers in Energy Research 2021, 9 (70). https://doi.org/10.3389/fenrg.2021.651041.(14) Ragones, H. et al. Towards Smart Free Form-Factor 3D Printable Batteries. Sustainable Energy & Fuels 2018, 2 (7), 1542–1549.(15) Egorov, V. et al. Evolution of 3D Printing Methods and Materials for Electrochemical Energy Storage. Adv. Mater. 2020, 32 (29). https://doi.org/10.1002/adma.202000556.(16) Murphy, P. STMD’s New Strategic Framework Update, 2017. https://www.nasa.gov/sites/default/files/atoms/files/336429-508-to5_nac_dec_2017_strategicplanningintegration_tagged.pdf.(17) Maurel, A. et al. What Would Battery Manufacturing on the Moon and Mars Look Like? (submitted).(18) Maurel, A. et al. 3D Printed TiO2 Negative Electrodes for Sodium-Ion and Lithium-Ion Batteries Using Vat Photopolymerization (submitted).

Influence of temperature field on the rheological properties and photopolymerization process of Mg2TiO4 microwave ceramic slurry during vat photopolymerization process

Influence of temperature field on the rheological properties and photopolymerization process of Mg2TiO4 microwave ceramic slurry during vat photopolymerization process

Biochar filler in MEX and VPP additive manufacturing: characterization and reinforcement effects in polylactic acid and standard grade resin matrices

The development of sustainable and functional biocomposites remains a robust research and industrial claim. Herein, the efficiency of using eco-friendly biochar as reinforcement in Additive Manufacturing (AM) was investigated. Two AM technologies were applied, i.e., vat photopolymerization (VPP) and material extrusion (MEX). A standard-grade resin in VPP and the also eco-friendly biodegradable Polylactic Acid (PLA) in the MEX process were selected as polymeric matrices. Biochar was prepared in the study from olive trees. Composites were developed for both 3D printing processes at different biochar loadings. Samples were 3D-printed and mechanically tested after international test standards. Thermogravimetric Analysis and Raman revealed the thermal and structural characteristics of the composites. Morphological and fractographic features were derived, among others, with Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Biochar was proven to be sufficient reinforcement agent, especially in the filament MEX process, reaching more than 20% improvement at 4 wt.% loading in tensile strength compared to the pure PLA control samples. In the VPP process, results were not as satisfactory, still, a 5% improvement was achieved in the flexural strength with 0.5 wt.% biochar loading. The findings prove the strong potential of biochar-based composites in AM applications, too.Graphical