Recyclable Amphiphilic Magnetic-responsive Mixed-Shell Nanoparticles With High Interfacial Activity Comparable to Janus Particles for Oily Water Purification.

Amphiphilic magnetic-responsive mixed-shell nanoparticles (Mag-MSNPs) with tailorable compositions are synthesized by electrostatic-mediated cross-linking of core-forming blocks of two diblock copolymers, followed by in situ growth of magnetite in the cross-linked core. The Mag-MSNPs have a magnetic-responsive core and hydrophilic/lipophilic mixed shells, firmly anchoring at the oil-water interface of emulsified oil droplets due to their high interfacial activity (13.1 mN m at a rather low emulsifier concentration of 1.

Stably Grafting Polymer Brushes on Both Active and Inert Surfaces Using Tadpole-Like Single-Chain Particles with an Interactive "Head".

We report a "grafting to" method for stably grafting high-molecular-weight polymer brushes on both active and inert surfaces using tadpole-like single-chain particles (TSCPs) with an interactive "head" as grafting units. The TSCPs can be efficiently synthesized through intrachain cross-linking one block of a diblock copolymer; the "head" is the intrachain cross-linked single-chain particle, and the "tail" is a linear polymer chain that has a contour length up to micrometers. When grafted to a surface, the "head", integrating numerous interacting groups, can synergize multiple weak interactions with the surface, thereby enabling stable grafting of the "tail" on both active and traditionally challenging inert surfaces.

Boosting Organic Afterglow Performance via a Two-Component Design Strategy Extracted from Macromolecular Self-Assembly.

Because intersystem crossing and phosphorescence decay are spin-forbidden in organic systems, it is challenging to obtain high-performance organic afterglow materials. Inspired by two-component design strategy from macromolecular self-assembly, here we report the utilization of synthetic polymers to control the excited state properties of difluoroboron β-diketonate (BFbdk) and deuterated BFbdk compounds for the fabrication of room-temperature organic afterglow materials. The polymer component can interact with BFbdk excited states by dipole-dipole interactions, lower BFbdk S levels with insignificant effect on T levels, reduce Δ, and thus enhance intersystem crossing of BFbdk excited states.

Noncovalent Postmodification Guided Reversible Compartmentalization of Polymeric Micelles.

Compartmentalized micelles (CMs) are promising tailor-made soft matters that mimic natural designed structures and functions. Despite the structure of complex CMs, manipulating CM structures accessibly and reversibly remains elusive. Here, we report the fabrication of CMs via a generally valid noncovalent postmodification process.

Effectiveness of varicella vaccine as post-exposure prophylaxis: a meta-analysis.

Background: To evaluate the effectiveness of varicella vaccine (VarV) as post-exposure prophylaxis (PEP) among children during varicella outbreaks.

Material And Methods: A comprehensive literature search was performed in PubMed, Embase, Web of Science, SinoMed, Wanfang and CNKI. Relevant outcomes included the incidence of varicella.

A novel worm-like micelles@MOFs precursor for constructing hierarchically porous CoP/N-doped carbon networks towards efficient hydrogen evolution reaction.

Constructing electrocatalysts with plentiful active sites, great mass transfer ability, and high electrical conductivity is critical to realize efficient hydrogen evolution reaction (HER). Hierarchically porous cobalt phosphide/N-doped nanotubular carbon networks (CoP/NCNs) that have all the features were fabricated in this work. For the fabrication, the polymeric worm-like micelles (PWs) with a large aspect ratio were coated by a uniform nanolayer of Zn-Co zeolitic imidazolate frameworks (Zn-Co-ZIFs) on their surface, resulting in the hybrid nanofibers PWs@Zn-Co-ZIFs (HPWs).

Strictly sparse surface modification and its application for endowing nanoparticles with an exact "valency".

Sparsely modified surfaces can be used as a general platform for precisely modifying small nanoparticles. However, strictly, rather than statistically, sparse surface modification remains a big challenge. Herein, we report a new and general method for strictly sparse modification of the surface of relatively large nanoparticles.

Fabrication of the Polymersomes with Unique and Even Nonequilibrium Morphologies.

Herein, efficient fabrication of polymersomes that have unique and nonequilibrium morphologies is reported. Starting from preparing big polymeric vesicles sized around 2 µm with a flexible but crosslinkable structure, a controllable morphological transformation process from the vesicles via prolate vesicles and the pearl-chain-like structure, which are the two intermediate structures, to vesicle-end-capped tubes is conducted. Significantly, each of the intermediates is a regular polymersome and occupies a distinct phase space in the transformation process and thus can be separately processed and prepared.

In situ synthesis of polyaniline/carbon nanotube composites in a carbonized wood scaffold for high performance supercapacitors.

Carbonized and activated wood scraps are appealing scaffolds upon which to host active materials for supercapacitors, realizing the transformation of waste into a valuable device. However, the active material when loaded on the inner walls of the wood tracheids can be easily peeled off, resulting in poor cycling stability of the capacitor and low energy density. Here, we designed a novel composite electrode material for high-performance supercapacitors based on a polyaniline/carbon nanotube composite material with a core-shell structure synthesized in situ in a carbonized wood scaffold.

Multistage Polymerization Design for g-CN Nanosheets with Enhanced Photocatalytic Activity by Modifying the Polymerization Process of Melamine.

Graphene-like g-CN nanosheets (NSs) have been successfully synthesized with a modified polymerization process of melamine by cocondensation with volatile salts. Volatile ammonium salts such as urea-NHCl/(NH)SO/(NH)PO were added with melamine to modulate the thermodynamic process during polymerization and optimize the structure formation in situ. The surface area, surface structure, and surface charge state of the obtained g-CN NSs could be controlled by simply adjusting the mass ratio of the melamine/volatile ammonium salt.

Endowing Polymeric Assemblies with Unique Properties and Behaviors by Incorporating Versatile Nanogels in the Shell.

Herein, we report an example of self-driven morphological transition and the unique dissociation behavior of polymeric assemblies. Polymeric nanogels were introduced into the shell of polymeric assemblies and used as a powerful platform to endow the assemblies with unique properties and behaviors. It is exhibited that the nanogel can host an intrananogel cross-linking reaction and thus contracts automatically to change the geometrical packing parameters of the building blocks, driving morphological transitions of the assemblies; the transitions are self-driven without any external stimuli.

Efficient Fabrication of Pure, Single-Chain Janus Particles through Their Exclusive Self-Assembly in Mixtures with Their Analogues.

We report the first example of the fabrication of pure, single-chain Janus particles (SCJPs). The SCJPs were prepared by double-cross-linking an A--B diblock copolymer in a common solvent. Inevitably, the double-cross-linking led to a mixture containing not only SCJPs but also multichain particles and irregular single-chain particles.

From Tunable DNA/Polymer Self-Assembly to Tailorable and Morphologically Pure Core-Shell Nanofibers.

In reported experimental studies, DNA/polymer self-assemblies are usually kinetically trapped, leading to the encapsulation and irregular collapse of DNA chains within the resultant assemblies. In striking contrast, eukaryotic cells use tetrasome-to-nucleosome pathways to escape possible kinetic trapping for the formation of well-defined 10 nm chromatin fibers. Here, we report a novel pathway for DNA and amphiphilic diblock copolymer self-assembly inspired by the tetrasome pathway with highly controllable kinetics.

Precise surface structure of nanofibres with nearly atomic-level precision.

We report the first example of endowing the surface structure of a polymeric assembly with nearly atomic-level precision. The solenoidal wrapping of a DNA chain around the surface of a nanofibre transcribes the precise sequence structure of the DNA onto the nanofibre surface, resulting in a precise surface structure.

Effectiveness of post-exposure prophylaxis during varicella outbreaks among primary and middle school students in Shanghai: An analysis of three-year surveillance data.

Objectives: To evaluate the effectiveness of post-exposure prophylaxis conducted during varicella outbreaks among students in Shanghai.

Methods: Surveillance data were collected from September 1, 2013 to December 31, 2016 involving 3524 susceptible students in 109 primary and middle school classes where emergency vaccinations (EVs) had been administered. Students were divided into two groups according to their prior vaccination (PV) varicella vaccine status.

Solution-Based Thermodynamically Controlled Conversion from Diblock Copolymers to Janus Nanoparticles.

Nanosized polymeric Janus particles (NPJPs) have important applications in a variety of theoretical and practical research fields. However, the methods that are versatile and can prepare NPJPs highly efficiently are very limited. Herein, we reported a two-step thermodynamically controlled preparation of NPJPs with a high yield using a diblock copolymer as the precursor.

Multiheteroatom-Doped Porous Carbon Catalyst for Oxygen Reduction Reaction Prepared using 3D Network of ZIF-8/Polymeric Nanofiber as a Facile-Doping Template.

We report a facile and versatile method for fabrication of multiheteroatom-doped hierarchically porous carbon with a large specific surface area, using the 3D network constructed by ZIF-8 coated wormlike micelles as template. The uniform and highly pure wormlike micelles developed in our laboratory is essential, because they not only are responsible for the formation of hierarchical porosity, but also play as a versatile platform for multiheteroatoms doping. In a primary experiment, S, N, B, and P heteroatoms were doped conveniently and the resultant porous carbons have the excellent oxygen reduction reaction performance comparable to the commercial 20% Pt/C.

Self-assembly of polymeric micelles into complex but regular superstructures based on highly controllable core-core fusion between the micelles.

Herein, we report a facile but highly controllable method to induce core-core fusion for not only spherical but also worm-like polymeric micelles, leading to various complex but regular superstructures including "random worm-like co-micelles", "block worm-like co-micelles" and octopus-like superparticles.

Recovering 3D images of polymeric nanofibers in solution through theoretical analysis and Monte-Carlo simulations of their 2D TEM images.

Nanofibers are well-known nanomaterials that are promising for many important applications. Since sample preparation for the applications usually starts from a nanofiber solution, characterization of the original conformation of nanofibers in the solution is significant because the conformation affects remarkably the behavior of nanofibers in the samples. However, the characterization is very difficult by existing methods: light scattering can only roughly evaluate the conformation in solution; cryo-TEM is laborious, time-consuming, and challenging technically, and thus difficult to study a system statistically.

Solution-Based Fabrication of Narrow-Disperse ABC Three-Segment and Θ-Shaped Nanoparticles.

Nanoparticles sized tens of nm with not only a highly complex but also a highly regular nanostructure, although ubiquitous in nature, are very difficult to prepare artificially. Herein, we report efficient solution-based preparation of narrow-disperse ABC three-segment hierarchical nanoparticles (HNPs) with a size of tens of nm through a three-level hierarchical self-assembly of A-b-B-b-C triblock copolymers in solution. An ABC HNP is composed of three nanoparticles, A, B, and C that are linearly connected; in the ABC HNP, the B nanoparticle is sandwiched between the A and C nanoparticles.

pH-activated size reduction of large compound nanoparticles for in vivo nucleus-targeted drug delivery.

Nucleus-targeted drug delivery is a promising strategy for anticancer therapy, but in vivo nucleus-targeted drug delivery has been challenging. Limited by the channel size of the nucleopore, vehicles that enter the nucleus via the nucleopore actively should be small and decorated with nuclear localization signal (NLS). However, the small vehicle size may promote leakage of vehicles into normal tissues, and the positively-charged NLS can lead to strong non-specific interactions in vivo.

Polymer Adsorption on Graphite and CVD Graphene Surfaces Studied by Surface-Specific Vibrational Spectroscopy.

Sum-frequency vibrational spectroscopy was employed to probe polymer contaminants on chemical vapor deposition (CVD) graphene and to study alkane and polyethylene (PE) adsorption on graphite. In comparing the spectra from the two surfaces, it was found that the contaminants on CVD graphene must be long-chain alkane or PE-like molecules. PE adsorption from solution on the honeycomb surface results in a self-assembled ordered monolayer with the C-C skeleton plane perpendicular to the surface and an adsorption free energy of ∼42 kJ/mol for PE(H(CH2CH2)nH) with n ≈ 60.

Hierarchically arranged helical fibre actuators driven by solvents and vapours.

Mechanical responsiveness in many plants is produced by helical organizations of cellulose microfibrils. However, simple mimicry of these naturally occurring helical structures does not produce artificial materials with the desired tunable actuations. Here, we show that actuating fibres that respond to solvent and vapour stimuli can be created through the hierarchical and helical assembly of aligned carbon nanotubes.

The natural degradation of benzophenone at low concentration in aquatic environments.

The natural degradation caused by sun irradiation and microbes in aquatic environments is of major significance in the elimination process of benzophenone (BP). In this study, the fate of BP in surface water at a low concentration of 10 μg/L was investigated, including both photodegradation and microbial degradation. The result showed that the photodegradation rate of BP was affected by several parameters such as the initial concentration, continuous input, and the presence of the analogue, ions and small molecules.

Solution-based fabrication of a highly catalytically active 3D network constructed from 1D metal-organic framework-coated polymeric worm-like micelles.

A 3D network constructed from metal-organic framework composite nanowires with a uniform width and a loose (swollen) structure has been prepared. It contained micro-, meso- and macro-pores, which make the 3D network ideal for use as a catalyst, as evidenced by its high catalytic activity in the Knoevenagel reaction.