Additive Manufacturing of Carbides using Renewable resources

We present preliminary experiments leading to novel additive manufacturing of carbides using a biopolymer-metal oxide composite as the precursor material. Renewable biopolymers replace petroleum-based ones as carbon source; and the temperature needed for carbide formation is drastically reduced due the colloidal proximity of the reactants. Additive manufacturing of a precursor gel composite could enable complex shapes, especially those currently challenging for powder pressing or machining of bulk carbides. To this end, we characterized water-based gels featuring iota-carrageenan (IC) as matrix; cellulose or chitin as fillers; and silica nanoparticles. Composite synthesis featured addition of a mixture of iota-carrageenan and chitin or cellulose to a silica nanoparticle dispersion. . Different 3D shapes were made with the composites by manual extrusion using a syringe. After heat treatment at 1300 °C in a nitrogen environment, carbonaceous 3D shapes were obtained. SEM-EDX, BET and XRD analysis were performed on the carbonaceous samples towards characterizing their composition and geometry. These results reveal a highly porous and amorphous material. Ongoing work is optimizing the heat treatment protocol and implementing a linear motion stage to enable additive manufacturing

Real-time degradation of methylene blue using bio-inspired superhydrophobic PDMS tube coated with Ta-ZnO composite

Dyes are widely used in a variety of industrial applications for aesthetical purpose as well as to provide the color of their products. Huge amount of dye-containing wastewater is released after their processing, posing a risk of environmental contamination. This has prompted the development of low-cost, highly reliable, and long-term technologies for effluent remediation. In this work, the synthesized tantalum (Ta)-doped Zinc oxide (ZnO) composite coated over the bioinspired polymeric platform has been reported for the decolouration of methylene blue (MB) dye when exposed to UV light. These structures were carefully investigated using a scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and a contact angle (CA) goniometer. The contact angle results show the contact angle of 108˚ for pure polydimethylsiloxane (PDMS) and 168˚ for bio-inspired PDMS with Ta-doped ZnO composite leading to a superhydrophobic surface. This superhydrophobic bio-inspired polymeric platform was modified by optimizing the surface roughness and coating it with low-surface-energy Ta-ZnO NWs composites, paving the way for it to be envisioned in "self-cleaning" water treatment facilities. When exposed to UV light, the MB dye degradation time was reduced from 150 mins to 105 mins, indicating that the synthesized Ta-doped ZnO NWs composite is more effective than ZnO. These photocatalysts lead to "waste control using Ta-ZnO NWs composites," which opens up new possibilities for flexible and biocompatible environmental remediation platforms. In this study, real-time MB dye degradation is also monitored using the Internet of things (IoT) technique by integrating a NodeMCU microcontroller board as a control center and a pH sensor as a tool for detecting the change in pH value of the MB dye under UV light exposure

Fabrication of High Surface Area Microporous ZnO from ZnO/Carbon Sacrificial Composite Monolith Template

Fabrication of porous materials from the standard sacrificial template method allows metal oxide nanostructures to be produced and have several applications in energy, filtration and constructing sensing devices. However, the low surface area of these nanostructures is a significant drawback for most applications. Here, we report the synthesis of ZnO/carbon composite monoliths in which carbon is used as a sacrificial template to produce zinc oxide (ZnO) porous nanostructures with a high specific surface area. The synthesized porous oxides of ZnO with a specific surface area of 78 m(2)/g are at least one order of magnitude higher than that of the ZnO nanotubes reported in the literature. The crucial point to achieving this remarkable result was the usage of a novel ZnO/carbon template where the carbon template was removed by simple heating in the air. As a high surface area porous nanostructured ZnO, these synthesized materials can be useful in various applications including catalysis, photocatalysis, separation, sensing, solar energy harvest and Zn-ion battery and as supercapacitors for energy storage

Taxonomy for engineered living materials

Engineered living materials (ELMs) are the most relevant contemporary revolution in materials science and engineering. These ELMs aim to outperform current examples of "smart", active or multifunctional materials, enabling countless industrial and societal applications. The "living" materials facilitate unique properties, including autonomy, intelligent responses, self-repair, and even self-replication. Within this dawning field, most reviews and documents have divided ELMs into biological ELMs, which are solely made of cells, and hybrid living materials, which consist of abiotic chassis and living cells. Considering that the most relevant feature of living material is that they are made of (or include) living cell colonies and microorganisms, we consider that ELMs should be classified and presented differently, more related to life taxonomies than materials science disciplines. Towards solving the current need for the classification of ELMs, this study presents the first complete proposal of taxonomy for these ELMs. Here, life taxonomies and materials classifications are hybridized hierarchically. Once the proposed taxonomy is explained, its applicability is illustrated by classifying several examples of biological ELMs and hybrid living materials, and its utility for guiding research in this field is analyzed. Finally, possible modifications and improvements are discussed, and a call for collaboration is launched for progressing in this complex and multidisciplinary field

Taxonomy for engineered living materials

Engineered living materials (ELMs) are the most relevant contemporary revolution in materials science and engineering and aim to outperform current examples of “smart,” active, or multifunctional materials, enabling countless industrial and societal applications. The “living” materials facilitate unique properties, including autonomy, intelligent responses, self-repair, and even self-replication. Within this dawning field, current literature has classified ELMs mainly into biological ELMs (bio-ELMs), which are solely made of cells, and hybrid living materials (HLMs), consisting of abiotic scaffold and living cells. Considering that the most relevant feature of ELMs is the living cell colonies or micro-organisms, we consider that ELMs should be classified and presented differently, more related to life taxonomies than to materials science disciplines. Toward solving the current need for the classification of ELMs, this study presents the first complete proposal of taxonomy for these ELMs. Here, life taxonomies and materials classifications are hybridized hierarchically. Once the proposed taxonomy is explained, its applicability is illustrated by classifying several examples of bio-ELMs and HLMs, and its utility for guiding research in this field is analyzed. Finally, possible modifications and improvements are discussed, and a call for collaboration is launched for progressing in this complex and multidisciplinary field

Enrichment of diluted cell populations from large sample volumes using 3D Carbon-electrode Dielectrophoresis

Here, we report on an enrichment protocol using carbon electrodedielectrophoresis to isolate and purify a targeted cell population from sample volumes up to 4 ml. We aim at trapping, washing, and recovering an enriched cell fraction that will facilitate downstream analysis. We used an increasingly diluted sample of yeast, 106–102 cells/ml, to demonstrate the isolation and enrichment of few cells at increasing flow rates. A maximum average enrichment of 154.2 ± 23.7 times was achieved when the sample flow rate was 10 μl/min and yeast cells were suspended in low electrically conductive media that maximizes dielectrophoresis trapping. A COMSOL Multiphysics model allowed for the comparison between experimental and simulation results. Discussion is conducted on the discrepancies between such results and how the model can be further improved