Custom 3D Printed Spatial Atomic Layer Deposition Manifold for the Coating of Tubular Membranes

Abstract

The development of highly efficient membranes represents a great opportunity to significantly reduce the environmental impacts of human activities through gas separation and water filtration; they are also very attractive for process intensification when coupled to existing industrial processes. Tubular membranes have higher modularity and better pressure resistance, and they offer easier sealing than their flat counterparts. The ability to deposit thin films on their surfaces is crucial to optimize their chemical and physical properties. However, the deposition of thin films on tubular membrane supports with conventional vacuum-based deposition techniques is relatively complex, slow, and costly. In this work, the versatility of spatial atomic layer deposition (SALD) and 3D printing technologies has been combined to design and fabricate a custom SALD manifold for coating tubular substrates. SALD is a scalable deposition technique, offering high throughput at atmospheric pressure and thus can be advantageously employed to coat tubular membranes, enabling high quality thin films to be deposited at the nanoscale considerably faster than with other conventional techniques. Computational fluid dynamics calculations by means of COMSOL Multiphysics have been used to optimize this innovative SALD gas manifold. The proof-of-concept method of the tubular/cylindrical SALD manifold has been validated through successful ZnO thin film depositions performed on tubular Cu foils and porous Al2O3 tubular membrane supports, demonstrating the capability of SALD to achieve high-throughput depositions on nonplanar, complex substrates. These results open prospects for the interface engineering of membranes or electrolyzers, where precise coatings of tubular surfaces are needed.

Assessing the Environmental Impact of Atomic Layer Deposition (ALD) Processes and Pathways to Lower It

“…In addition, the system can be easily adapted to the substrate geometry by modifying the design and size of the head, while the rest of the system remains equal. An example is the development of a SALD cylindrical head to coat tubular membranes . Several heads could be even combined in a modular approach yielding even higher throughput and contributing to lower precursor waste. − By adjusting the design of the head, the deposition can also be limited to a certain zone, thus having Area-Selective Deposition (ASD) without the need to prepattern the substrate (i.e., reducing the fabrication steps).…”

Gas‐Separating Metal‐Organic Framework Membrane Films on Large‐Area 3D‐Printed Tubular Ceramic Scaffolds

“…[9] That 3D-printing has a tremendous potential also for membrane science is a widely accepted fact [10] and, thus, has found cautious first applications in polymeric membrane systems [11] or as structured substrates [12] mainly for use in water purification, or for devices to coat tubular membranes. [13] Metal-organic frameworks (MOFs) are crystalline hybrid materials with permanent porosity that are synthesized following reticular chemistry. [14] They consist of metal ions or metaloxo clusters interconnected by the big toolbox of organic ligands.…”

Can We Rationally Design and Operate Spatial Atomic Layer Deposition Systems for Steering the Growth Regime of Thin Films?

“…13 Importantly, optimizing the design of the SALD head is particularly promising for future developments, given the ease of customizing SALD heads via rapid prototyping techniques, e.g., 3D-printing. 17,24 Some of the parameters that can be leveraged to minimize the mixing of precursors during deposition of thin films have been identified. For instance, decreasing the gap between the substrate and the deposition head and increasing the flow rate of the separation gas have been shown to prevent precursor mixing in SALD systems for porous, 25 nonporous, 26−29 and microgroove 30 substrates.…”

“…Various parameters influence whether a deposition occurs in ALD or CVD regimes when using SALD heads: operational parameters such as the deposition gap and the chosen flow rates and head design parameters such as the width of the gas channels and the thickness of the channel walls . Importantly, optimizing the design of the SALD head is particularly promising for future developments, given the ease of customizing SALD heads via rapid prototyping techniques, e.g., 3D-printing. , …”

“… 13 Importantly, optimizing the design of the SALD head is particularly promising for future developments, given the ease of customizing SALD heads via rapid prototyping techniques, e.g., 3D-printing. 17 , 24 …”