Editorial for the Special Issue "Materials under High Pressure".

The high-pressure-related problems of materials constitute a field at the confluence of several scientific disciplines [...

Chiral Confined Unimolecular Micelles for Controlled Fabrication of Optically Active Hybrid Nanostructures.

Functional nanomaterials made by chiral induction have attracted extensive attention because of their intriguing characteristics and potential applications. However, the precise and controllable fabrication of chiral nanomaterials still remains challenging but is highly desired. In this study, chiral unimolecular micelles with different molecular weights and chiroptical activities were prepared by photoinduced atom transfer radical polymerization (photoATRP).

Simple preparation of lignosulfonate stabilized eutectic gallium/indium liquid metal nanodroplets through ball milling process.

The combination of biomass and liquid metal (LM) makes the preparation process "greener" and application of LM composite materials more sustainable. Here we reported the solvent free preparation of lignosulfonate (LS) stabilized eutectic gallium/indium (EGaIn) LM nanodroplets through ball milling (BM), which was recognized to be efficient and environmentally-friendly alternatives to solution-based methods. By regulating the BM frequency and milling time, uniform LM nanodroplets with a size <200 nm can be achieved.

Robust Strategy to Improve the Compatibility between Incorporated Upconversion Nanoparticles and the Bulk Transparent Polymer Matrix.

Traditional transparent polymer nanocomposites combined with functional fluorescent inorganic nanofillers are promising for many advanced optical applications. However, the aggregation of the incorporated functional nanoparticles results in light scattering and will decrease the transparency of nanocomposites, which will restrain the application of the transparent nanocomposites. Herein, a robust synthesis strategy was proposed to modify upconversion nanoparticles (UCNPs) with polymethyl methacrylate (PMMA) to form UCNP@PMMA core@shell nanocomposites though metal-free photoinduced surface-initiated atom transfer radical polymerization (photo-SI-ATRP), and thus, the dispersity of UCNP@PMMA and the interface compatibility between the surface of UCNPs and the bulk PMMA matrix was greatly improved.

Hierarchically Structured Nanotube Arrays as Heterogenous Photocatalysts for Highly Efficient Broadband Photoinduced Controlled Radical Polymerization.

Highly ordered TiO nanotube arrays (TNTAs) and their heterostructure nanocomposites by structural engineering design were utilized as heterogeneous photocatalysts for highly efficient broadband photoinduced controlled radical polymerization (photoCRP), including photoATRP and PET-RAFT. Highly efficient broadband UV-visible light responsive photoCRP was achieved by combining the acceleration effects of electron transfer derived from the distinctive highly ordered nanotube structure of TNTAs and the localized surface plasmon resonance (LSPR) effect combined with the formation of the Schottky barrier via modification of Au nanoparticles. This polymerization system was capable to polymerize acrylate and methacrylate monomers with high conversion, "living" chain-ends, tightly regulated molecular weights, and outstanding temporal control properties.

Mechanically Driven Atom Transfer Radical Polymerization by Piezoelectricity.

Targeting sustainable and eco-friendly polymer synthesis, we demonstrate here a synergistically catalyzed atom transfer radical polymerization (ATRP) induced and controlled by interplay between ball milling (BM) and piezoelectric nanoparticles (piezoNPs). BM-induced electron transfer can be achieved through piezoNPs deformation under impact force, serving as an external stimulus to mediate polymerization. The ppm level of copper loading is sufficient in fabrication of a polymer with well-defined molecular weight and low polydispersity.

Silver Nanocrystal Array with Precise Control via Star-like Copolymer Nanoreactors.

Silver nanocrystal arrays had attracted much attention due to the unique plasmonic effect of their ordered nanostructure and the synergy among adjacent nanocrystals. Conventional preparation methods had several limitations, such as high cost, harsh preparation conditions, and complicated influencing factors, which could not be employed to fabricate the nanocrystal arrays in highly controlled fashion. To solve these issues, we reported ordered arrays of different Ag nanocrystals with precise control prepared by utilizing amphiphilic star-like poly(4-vinylpyridine)--polystyrene diblock copolymers as nanoreactors synthesized by sequential atom transfer radical polymerization.

Carbon Quantum Dot-Catalyzed, Highly Efficient Miniemulsion Atom Transfer Radical Polymerization Induced by Visible Light.

Owing to the benefits of using natural or artificial light sources as a stimulus, photoinduced reversible-deactivation radical polymerization (photoRDRP) techniques have been recognized to be a powerful "green" platform for the preparation of well-defined polymers. However, the development of highly efficient visible light-induced photoRDRP processes in aqueous dispersed media remains a challenge due to light scattering and refraction by monomer droplets or colloidal particles. In this work, an efficient green photocatalyst, carbon quantum dots (CQDs), was introduced to visible light-mediated miniemulsion atom transfer radical polymerization (ATRP), leading to highly efficient polymerizations with reaction rates (>80% monomer conversion within 1 h) much higher than in previous studies.

Dimensional Optimization for ZnO-Based Mechano-ATRP with Extraordinary Activity.

Various piezoelectric nanomaterials were utilized in ultrasound-mediated atom transfer radical polymerization (ATRP), owing to their outstanding piezoelectric effect. However, the relationship between the morphology of those piezocatalysts and polymerization has not been clearly established. Herein, we employed different piezoelectric zinc oxide (ZnO) nanomaterials to achieve novel mechano-induced ATRP (mechano-ATRP).

Ultrafast Visible-Light-Induced ATRP in Aqueous Media with Carbon Quantum Dots as the Catalyst and Its Application for 3D Printing.

Photoinduced atom transfer radical polymerization (ATRP) has been proved to be a versatile technique for polymer network formation. However, the slow polymerization rates of typical ATRP limited its application in the field of additive manufacturing (3D printing). In this work, we introduced carbon quantum dots (CQDs) for the first time to the ATRP in aqueous media and developed an ultrafast visible-light-induced polymerization system.

Simple Full-Spectrum Heterogeneous Photocatalyst for Photo-induced Atom Transfer Radical Polymerization (ATRP) under UV/vis/NIR and its Application for the Preparation of Dual Mode Curing Injectable Photoluminescence Hydrogel.

The utilizing light with broadband range has attracted lots of research interest for the photo induced reversible-deactivation radical polymerization (RDRP). However, it is still a challenge for a single catalyst to simultaneously respond to various lights with highly varied wavelengths. Here, we proposed a simple strategy for the preparation of a heterogeneous photocatalyst suitable for photo induced atom transfer radical polymerization (photoATRP) under full spectrum (from UV/vis light to NIR), by combining pyridine nitrogen doped carbon dots (N-CDs) and upconversion nanoparticles (UCNPs).

General Route to Colloidal Nanocrystal Clusters with Precise Hierarchical Control via Star-like Nanoreactors.

A colloidal nanocrystal cluster (CNC) is a hierarchical nanostructure formed by clustering several nanocrystals into one nano-ensemble, which may exhibit unique optical or catalytic properties different from individual nanocrystals owing to the mutual interactions among neighboring component nanocrystals. However, there is still no universal synthetic route that could be applicable to diverse material compositions with precisely controlled hierarchical structures (i.e.

From Unimolecular Template to Silver Nanocrystal Clusters: An Effective Strategy to Balance Antibacterial Activity and Cytotoxicity.

Silver nanomaterials have attracted a great deal of interest due to their broad-spectrum antimicrobial activity. However, it is still challenging to balance the high antibacterial efficiency with low damage to biological cells of silver nanostructures, especially when the diameter decreases to less than 10 nm. Here, we developed a new type of Ag nanohybrid material via a unimolecular micelle template method, which presents amazing antibacterial activities and almost noncytotoxicity.

Preparation of highly colloidal stable Yolk-Shell nanocomposite and its multi-stimuli responsive based on surface aggregation-induced emission (S-AIE).

Multi-stimuli responsive fluorescence probe could pave the way for monitoring more complex environmental changes. Here we prepared multifunctional nanoparticle FeO@SiO@P(DMAEMA-co-TPEE), which displayed yolk-shell morphology with well-defined polymer brush. With superparamagnetic FeO component and pH/temperature dual sensitive PDMAEMA polymer brush, the as prepared nanoparticles (YS-NPs) exhibited as multi-stimuli responsive fluorescence probe for real-time visual monitoring of environmental changes such as magnetic field, temperature and pH.

Unconventional Approach to Fabricating a TiO Nanoring with Precise Dimension Control Based on Starlike Polymeric Nanoreactors.

The past few years witnessed the rapid development of bottom-up synthesis strategies for preparing various nanostructures (i.e., nanoparticles, nanorods, nanowires, etc.

Dual Roles of Amino-Functionalized Silicon Quantum Dots (SiQDs) for Visible-Light-Induced Surface-Initiated PET-RAFT Polymerization on Substrates.

Silicon quantum dots (SiQDs) are explored for the first time as an efficient photocatalyst for visible-light-regulated reversible addition-fragmentation chain transfer (RAFT) polymerization. The fluorescence quenching confirmed the photoinduced electron transfer (PET) between SiQDs and RAFT reagents. Besides all features of controlled radical polymerization, the SiQDs catalyzed PET-RAFT polymerization also exhibit good temporal control, high chain-end fidelity, and versatility with diverse monomers.

A Versatile Strategy for Unimolecular Micelle-Derived Hollow Polymer Nanoparticles as General Nanoreactors.

We reported the synthesis of a well-defined hollow polymer nanoparticle derived from star-shaped unimolecular micelles. β-Cyclodextrin was first applied as an efficient macroinitiator to prepare a star-shaped PCL ring-opening polymerization (ROP). Then, the star-shaped PCL was modified to be a macro-RAFT agent for photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization of S-Cl monomers.

Light and magnetism dual-gated photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization.

A novel raspberry-like γ-FeO@carbon dot (CD) nanocatalyst was prepared and applied for photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. The nanocatalyst was found to be an efficient photocatalyst in visible light-regulated PET-RAFT polymerization owing to the oxidative quenching mechanism between the photoexcited γ-FeO@CDs and the RAFT agent in the PET process. Notably, polymerization can be reversibly ceased in the absence of light or under an external magnetic field.

Visualization of Atom Transfer Radical Polymerization by Aggregation-Induced Emission Technology.

Aggregation-induced emission (AIE) technology has been demonstrated to be a facile approach for in-situ monitoring atom transfer radical polymerization (ATRP). A series of tertraphenyl ethylene (TPE)-containing α-bromo compounds were synthesized and applied as ATRP initiators. The photoluminescent (PL) emission of the polymerization system is proved to be sensitive to the local viscosity owing to the AIE characteristics of TPE.

Star-poly(ε-caprolactone) as the stationary phase for capillary gas chromatographic separation.

This work presents the separation performance of star-poly(ε-caprolactone) (star-PCL) as the stationary phase for capillary gas chromatography (GC). The statically coated star-PCL column showed a column efficiency of 3345 plates per m and moderate polarity. Importantly, the star-PCL column exhibited high selectivity and resolving capability for more than a dozen mixtures covering a wide-ranging variety of analytes and isomers.