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

Fine control over the growth of materials is required to precisely tailor their properties. Spatial atomic layer deposition (SALD) is a thin-film deposition technique that has recently attracted attention because it allows producing thin films with a precise number of deposited layers, while being vacuum-free and much faster than conventional atomic layer deposition. SALD can be used to grow films in the atomic layer deposition or chemical vapor deposition regimes, depending on the extent of precursor intermixing. Precursor intermixing is strongly influenced by the SALD head design and operating conditions, both of which affect film growth in complex ways, making it difficult to predict the growth regime prior to depositions. Here, we used numerical simulation to systematically study how to rationally design and operate SALD systems for growing thin films in different growth regimes. We developed design maps and a predictive equation allowing us to predict the growth regime as a function of the design parameters and operation conditions. The predicted growth regimes match those observed in depositions performed for various conditions. The developed design maps and predictive equation empower researchers in designing, operating, and optimizing SALD systems, while offering a convenient way to screen deposition parameters, prior to experimentation.

Covalent transfer of chemical gradients onto a graphenic surface with 2D and 3D control.

Control over the functionalization of graphenic materials is key to enable their full application in electronic and optical technologies. Covalent functionalization strategies have been proposed as an approach to tailor the interfaces' structure and properties. However, to date, none of the proposed methods allow for a covalent functionalization with control over the grafting density, layer thickness and/or morphology, which are key aspects for fine-tuning the processability and performance of graphenic materials. Here, we show that the no-slip boundary condition at the walls of a continuous flow microfluidic device offers a way to generate controlled chemical gradients onto a graphenic material with 2D and 3D control, a possibility that will allow the sophisticated functionalization of these technologically-relevant materials.

Chirality transfer from a 3D macro shape to the molecular level by controlling asymmetric secondary flows.

Homochirality is a fundamental feature of living systems, and its origin is still an unsolved mystery. Previous investigations showed that external physical forces can bias a spontaneous symmetry breaking process towards deterministic enantioselection. But can the macroscopic shape of a reactor play a role in chiral symmetry breaking processes? Here we show an example of chirality transfer from the chiral shape of a 3D helical channel to the chirality of supramolecular aggregates, with the handedness of the helical channel dictating the direction of enantioselection in the assembly of an achiral molecule. By combining numerical simulations of fluid flow and mass transport with experimental data, we demonstrated that the chiral information is transferred top-down thanks to the interplay between the hydrodynamics of asymmetric secondary flows and the precise spatiotemporal control of reagent concentration fronts. This result shows the possibility of controlling enantioselectively molecular processes at the nanometer scale by modulating the geometry and the operating conditions of fluidic reactors.

Synthesis of 2D Porous Crystalline Materials in Simulated Microgravity.

To date, crystallization studies conducted in space laboratories, which are prohibitively costly and unsuitable to most research laboratories, have shown the valuable effects of microgravity during crystal growth and morphogenesis. Herein, an easy and highly efficient method is shown to achieve space-like experimentation conditions on Earth employing custom-made microfluidic devices to fabricate 2D porous crystalline molecular frameworks. It is confirmed that experimentation under these simulated microgravity conditions has unprecedented effects on the orientation, compactness and crack-free generation of 2D porous crystalline molecular frameworks as well as in their integration and crystal morphogenesis. It is believed that this work will provide a new "playground" to chemists, physicists, and materials scientists that desire to process unprecedented 2D functional materials and devices.

The use of algeness in the face and neck: a safe, alternative filler for cosmetics and reconstruction.

BACKGROUND: The search for effectiveness and safety in the use of dermal fillers, is an ongoing challenge for aesthetic physicians, plastic surgeons and the science of bioengineering. Understanding the variety of characteristics, capabilities, advantages and disadvantages of available injectables is essential to reduce complication rates and achieve satisfying aesthetic and functional results. METHODS: Algeness is a 100% natural, biodegradable tissue implant, consisting of a gel derived from agarose. This paper analyzes the use of this newly introduced agarose gel as an alternative filler in the face and neck for aesthetic and functional indications. All participants gave informed consent before taking part and there was no ethics approval required. As this work describes opinions based on clinical experienced physicians and not the results of a monocentric study. RESULTS: Algeness is competitive with other available hydrophilic biomaterials, such as hyaluronic acid, and has the advantage of its unique hydrocolloid nature. CONCLUSIONS: Compared to other injectables, it exhibits good tolerability, excellent persistence, negligible immunological reaction, biocompatibility and maximal safety-all properties combined with immediate volume restoration and predictable outcomes. "What you see (on injection), is what you get (as a result)". Level of evidence: Level V, opinions based on clinical experience.