Recent Progress on 3D Printing of Lightweight Metal Thin-Walled Structures.

Metal thin-walled structures are ubiquitous in various industrial applications and fabricating them through additive manufacturing (AM) enables intricate thin-wall geometries with no assembly required. However, additively manufactured metal thin walls suffer from increased heat accumulation and reduced structural stability, making it difficult to print geometrically accurate thin walls with minimal distortion and defects. Thin-walled structures also experience different thermal histories and solidification conditions compared to bulk structures, leading to drastic differences in the microstructure and mechanical properties.

Solidification/stabilisation behaviours of Zn in magnesium potassium phosphate cement: Experiments and density functional theory study.

The solidification/stabilisation behaviours of Zn in magnesium potassium phosphate cement (MKPC) have not been thoroughly investigated. Herein, a series of experiments and a detailed density functional theory (DFT) study were conducted to investigate the solidification/stabilisation behaviours of Zn in MKPC. The results showed that the compressive strength of MKPC reduced with the addition of Zn because the formation of MgKPO·6HO (the main hydration product in MKPC) was delayed with the addition of Zn, as discovered by the crystal characteristics, and because Zn exhibited a lower binding energy in MgKPO·6HO compared to Mg, as revealed by DFT results.

Atomistic Insights into the Tunable Transition from Cavitation to Crazing in Diamond Nanothread-Reinforced Polymer Composites.

Cavitation and crazing in thermosetting polymers can be sophisticatedly designed for valuable applications in optics, electronics, and biotechnology. It is a great challenge for numerical study to describe the formations of cavity and fibrils in polymer composite due to the complicated interfacial interaction. To explore this challenging task, we exploit a two-phase coarse-grained framework which serves as an efficient atomistic level-consistent approach to expose and predict the transition between cavitation and crazing in a polymeric system.

Multiresponsive Microgels with Phase-Separated Nanodomains and Self-Regulating Properties via Incorporation of Anthraquinone Moieties.

Of the multitude of stimuli-responsive microgels, it is still a challenge to achieve multiple responsivenesses to one single stimulus, which can even revert to the corresponding original state autonomously after stimulus. In this work, we reported a series of anthraquinone functionalized microgels (PNI-VAQ) with thermosensitivity and redox-actuated self-regulating color, size, and fluorescent properties, which were easily synthesized via surfactant-free emulsion copolymerization (SFEP) with -isopropylacrylamide (NIPAm) as the monomer, 2-vinylanthraquinone (VAQ) as the comonomer, and ,'-methylenebis(acrylamide) (BIS) as the cross-linker in an aqueous solution at 70 °C. The hydrophobic interactions of comonomer VAQ also led to the formation of internal phase-separated hydrophobic nanodomains in the obtained PNI-VAQ microgels.

Degradable and Thermosensitive Microgels with Tannic Acid as the Sole Cross-Linker.

Poly(-isopropylacrylamide) (PNIPAM)-tannic acid (TA) microgels were successfully prepared via surfactant-free emulsion polymerization (SFEP) at 70 °C in aqueous solution using -isopropylacrylamide (NIPAM) as the monomer and a natural polyphenol macromolecule, TA, as the sole cross-linker. The cross-linking network of the PNIPAM-TA microgels was confirmed to contain both physical cross-linking structures formed via hydrogen-bonding interactions between TA and PNIPAM chains and chemical cross-linking structures formed via capturing the radicals of propagating polymer chains by catechol and pyrogallol groups of TA. Furthermore, TA was applied to modify the surface of hydrophobic FeO nanoparticles, leading to hydrophilic FeO@TA composite nanoparticles, which were successfully used as the cross-linker to fabricate PNIPAM-FeO@TA organic-inorganic hybrid microgels.

Optical Detection of Fe Ions in Aqueous Solution with High Selectivity and Sensitivity by Using Sulfasalazine Functionalized Microgels.

A highly selective and sensitive optical sensor was developed to colorimetric detect trace Fe ions in aqueous solution. The sensor was the sulfasalazine (SSZ) functionalized microgels (SSZ-MGs), which were fabricated via in-situ quaternization reaction. The obtained SSZ-MGs had hydrodynamic radius of about 259 ± 24 nm with uniform size distribution at 25 °C.

Nano-Silica Sol-Gel and Carbon Nanotube Coupling Effect on the Performance of Cement-Based Materials.

Carbon nanotubes (CNTs) have shown promise for improving the mechanical performance of cement composites through crack-bridging and frictional pull-out. The interactive behaviors between CNTs and cement matrix act are crucial in optimizing the reinforcement of CNTs in cement composites. This study investigates the effects of nano-silica (NS) sol-gel on the interactive behaviors of CNTs and the cement matrix through a series of experiments and analyses.

Investigation on the Mechanical Properties of a Cement-Based Material Containing Carbon Nanotube under Drying and Freeze-Thaw Conditions.

This paper aimed to explore the mechanical properties of a cement-based material with carbon nanotube (CNT) under drying and freeze-thaw environments. Mercury Intrusion Porosimetry and Scanning Electron Microscopy were used to analyze the pore structure and microstructure of CNT/cement composite, respectively. The experimental results showed that multi-walled CNT (MWCNT) could improve to different degrees the mechanical properties (compressive and flexural strengths) and physical performances (shrinkage and water loss) of cement-based materials under drying and freeze-thaw conditions.