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Natural mollusks perform complex mechanical actions through reversible large-strain deformation and stiffness switching, which are challenging to achieve simultaneously in synthetic materials. Herein, it is shown that a set of polyacrylates designed according to a chain friction and lubrication balanced strategy shows ultra-stretchability (λ up to 324), high resilience (near 100% recovery at strain ≥ 100), and wide-span stiffness switching (up to 2073 times). The typical emulsion polymerization method and casting technique are adopted to fabricate the polyacrylate films. Quaternary ammonium surfactants are used as the emulsifier and reserved in the polymer matrix to enhance the chain segment lubrication with their long alkyl group but improve the whole chain friction through the formation of nano-eutectics. These polyacrylates undergo multimodal mechanical responses, including temperature- or time-programmed deformation and load-bearing like artificial muscles. This molecular design principle and synthetic method provide a robust platform for the fabrication of ultra-tough polymers for soft robots with multiple customized functions., (© 2024 Wiley‐VCH GmbH.)

Flexible and stretchable electronic devices are subject to failure because of vulnerable circuit interconnections. We develop a low-voltage (1.5 to 4.5 V) and rapid (as low as 5 s) electric welding strategy to integrate both rigid electronic components and soft sensors in flexible circuits under ambient conditions. This is achieved through the design of conductive elastomers composed of borate ester polymers and conductive fillers, which can be self-welded and generate welding effects to various materials including metals, hydrogels, and other conductive elastomers. The welding effect is generated through the electrochemical reaction-triggered exposure of interfacial adhesive promotors or the cleavage/reformation of dynamic bonds. Our strategy can ensure both mechanical compliance and conductivity at the circuit interfaces and easily produce welding strengths in the kilopascal to megapascal range. The as-designed conductive elastomers in combination with the electric welding technique provide a robust platform for constructing standalone flexible and stretchable electronic devices that are detachable and assemblable on demand.

Metal nanoclusters providing maximized atomic surface exposure offer outstanding hydrogen evolution activities but their stability is compromised as they are prone to grow and agglomerate. Herein, a possibility of blocking metal ion diffusion at the core of cluster growth and aggregation to produce highly active Ru nanoclusters supported on an N, S co-doped carbon matrix (Ru/NSC) is demonstrated. To stabilize the nanocluster dispersion, Ru species are initially coordinated through multiple Ru─N bonds with N-rich 4'-(4-aminophenyl)-2,2:6',2''-terpyridine (TPY-NH 2 ) ligands that are subsequently polymerized using a Schiff base. After the pyrolysis of the hybrid composite, highly dispersed ultrafine Ru nanoclusters with an average size of 1.55 nm are obtained. The optimized Ru/NSC displays minimal overpotentials and high turnover frequencies, as well as robust durability both in alkaline and acidic electrolytes. Besides, outstanding mass activities of 3.85 A mg -1 Ru at 50 mV, i.e., 16 fold higher than 20 wt.% Pt/C are reached. Density functional theory calculations rationalize the outstanding performance by revealing that the low d-band center of Ru/NSC allows the desorption of *H intermediates, thereby enhancing the alkaline HER activity. Overall, this work provides a feasible approach to engineering cost-effective and robust electrocatalysts based on carbon-supported transition metal nanoclusters for future energy technologies., (© 2023 Wiley‐VCH GmbH.)

Chemically modifying monolayer two-dimensional transition metal dichalcogenides (TMDs) with organic molecules provides a wide range of possibilities to regulate the electronic and optoelectronic performance of both materials and devices. However, it remains challenging to chemically attach organic molecules to monolayer TMDs without damaging their crystal structures. Herein, we show that the Mo atoms of monolayer MoS 2 (1L-MoS 2 ) in defect states can coordinate with both catechol and 1,10-phenanthroline (Phen) groups, affording a facile route to chemically modifying 1L-MoS 2 . Through the design of two isomeric molecules (LA2 and LA5) comprising catechol and Phen groups, we show that attaching organic molecules to Mo atoms via coordinative bonds has no negative effect on the crystal structure of 1L-MoS 2 . Both theoretical calculation and experiment results indicate that the coordinative strategy is beneficial for (i) repairing sulfur vacancies and passivating defects; (ii) achieving a long-term and stable n-doping effect; and (iii) facilitating the electron transfer. Field effect transistors (FETs) based on the coordinatively modified 1L-MoS 2 show high electron mobilities up to 120.3 cm 2 V -1 s -1 with impressive current on/off ratios over 10 9 . Our results indicate that coordinatively attaching catechol- or Phen-bearing molecules may be a general method for the nondestructive modification of TMDs.

Hydrogels have attracted widespread attention in anticounterfeiting due to their unique physical/chemical properties and designability. However, hydrogels' poor mechanical properties and sluggish response to chemical stimuli pose challenges for their wide application. A fluorescent tough organohydrogel capable of freeform writing of information is reported in this work. By incorporation of the fluorescent monomer 7-methylacryloxy-4-methylcoumarin into the polyacrylamide network in a covalently cross-linked manner while intertwining with the carboxymethyl cellulose sodium network, a fluorescent tough organohydrogel with a dual-network structure is prepared. The organohydrogel shows acid-base-mediated adjustable fluorescence through the transformation of fluorescent monomers. Ion printing and electrical stimulation design achieved free information storage and encryption. In addition, the prepared organohydrogel has good antifreezing properties and can be encrypted and decrypted at subzero temperatures. The encrypted information in the organohydrogel can be read only after UV-light irradiation. These patterned fluorescent organohydrogels should find applications in protected message displays for improved information security.

The underlying trend of colloidal synthesis has focused on extending the structure and composition complexity of colloidal particles. Hollow and yolk-shell particles are successful examples that have potential applications in frontier fields. In this paper, a facile and controllable etching method based on the molecular exchange of the dynamic imine bond to generate cavities in polymer particles is developed. Starting from boronate ester polymer particles and inorganic@boronate core-shell particles with the imine bonds incorporated in the polymer networks, the etching method easily affords hollow and yolk-shell particles with tunable shell thicknesses. The molecular exchange dynamics analysis indicates that guest amine molecules cause the reconstruction of imine bonds and the leakage of molecular and oligomer fragments, resulting in the formation of the hollow structure. This molecular exchange-based etching method may be of interest in the construction of polymer architectures with increased composition and structure complexities., (© 2022 Wiley-VCH GmbH.)

Metallopolymers combine the property features of both metallic compounds and organic polymers, representing a typical direction for the design of high-performance hybrid materials. Here, a highly adaptive etching method to create pores and cavities in the metallopolymer particles is established. Starting from boronate polymer (BP) and inorganic@BP core-shell particles, porous, hollow, and yolk-shell metallopolymer particles can be fabricated, respectively. By taking advantage of the easy control over composition and pore/cavity structure, these metallopolymer particles provide a universal platform for the fabrication of nitrogen, boron co-doped carbon nanocomposites loaded with metals (M-NBCs). The as-prepared M-NBCs exhibit remarkable catalytic activities toward oxygen evolution reaction and hydrogen evolution reaction. An alkaline overall water splitting cell assembled by using M-NBCs as the anode and cathode can be driven by a single AAA battery. The proposed strategy for the construction of metallopolymer composites may enlighten for the design of complex hybrid nanomaterials., (© 2022 Wiley-VCH GmbH.)

Stimuli-responsive supercapacitors have attracted broad interest in constructing self-powered smart devices. However, due to the demand for high cyclic stability, supercapacitors usually utilize stable or inert electrode materials, which are difficult to exhibit dynamic or stimuli-responsive behavior. Herein, this issue is addressed by designing a MoS 2 @carbon core-shell structure with ultrathin MoS 2 nanosheets incorporated in the carbon matrix. In the three-electrode system, MoS 2 @carbon delivers a specific capacitance of 1302 F g -1 at a current density of 1.0 A g -1 and shows a 90% capacitance retention after 10 000 charging-discharging cycles. The MoS 2 @carbon-based asymmetric supercapacitor displays an energy density of 75.1 Wh kg -1 at the power density of 900 W kg -1 . Because the photo-generated electrons can efficiently migrate from MoS 2 nanosheets to the carbon matrix, the assembled photo-responsive supercapacitor can answer the stimulation of ultraviolet-visible-near infrared illumination by increasing the capacitance. Particularly, under the stimulation of UV light (365 nm, 0.08 W cm -2 ), the device exhibits a ≈4.50% (≈13.9 F g -1 ) increase in capacitance after each charging-discharging cycle. The study provides a guideline for designing multi-functional supercapacitors that serve as both the energy supplier and the photo-detector., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Multifunctional cotton fabrics (M-CF) have important application prospects in intelligent home decoration and material packaging. In this work, nanoparticles (AgNC@BP) were prepared by coating the surface of silver nanocubes (AgNCs) with borate polymer. Subsequently, M-CF with electromagnetic wave (EMW) absorption, mechanical enhancement, flame-retardancy and antibacterial performances were prepared by immersing cotton fabrics (CF) into AgNC@BP/crosslinked chitosan (CS) solution. Expectantly, AgNC@BP endows AgNC@BP/CS-CF with good flame retardancy and low combustion heat release. That is, the char length of AgNC@BP/CS-CF is 7.9 cm after the vertical burning test (UL-94 V) and the peak heat release rate (pHRR) of AgNC@BP/CS-CF is reduced by 21.4% compared to pure CF. Meanwhile, the tensile strength of AgNC@BP/CS-CF is 18.8% higher than that of CF. Synchronously, the introduction of AgNC@BP can also endow M-CF with better EMW absorption, mechanical and antibacterial properties. In conclusion, this work provides a tactic for fabricating M-CF., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

We report a simple metal ion-catechol coordination strategy to coat ruthenium-catechol polymer complex (TAC-Ru) on the surface of carbon nanotubes (CNT) to form a core-shell structure (abbreviated as CNT@TAC-Ru). This is achieved by firstly polymerizing catechol and boronic acid monomers on the surface of CNT to form a boronate ester polymer (BP) shell. Then, Ru 3+ is used to etch the BP shell, and cleave the dynamic boronate ester bond, leading to the formation of a CNT@ruthenium-catechol coordination complex based on the coordinative efficiency of the catechol group. The electrocatalytic property of the CNT@TAC-Ru composite can be activated through electrochemical cycling treatment. The as-activated CNT@TAC-Ru exhibits evidently improved hydrogen evolution reaction (HER) performance with an overpotential of 10 mV in 1.0 M KOH at a current density of 10 mA cm -2 , which is better than that of commercial Pt/C (32 mV). And the long-term stability is also desirable. This work provides a pyrolysis-free method to form metal-polymer-carbon composite with high HER performance under the alkaline condition., (© 2022 IOP Publishing Ltd.)

In order to overcome the structural drawbacks of layered electrodes in flexible supercapacitors, the construction of an electrode frame with high adaptability for the loading of different active materials makes the production of flexible supercapacitors simpler and more accurate. Herein, a novel loader type flexible supercapacitor with three-dimensional hybrid structure is built. In our design, the acetylene black and active material are enriched in the polyvinyl alcohol matrix, and the three-dimensional conductive network that can load different active material is formed. The active material can be selected on demand. The basic electrode (also a loader) formed by polyvinyl alcohol and acetylene black is an electronic conductor (∼1 Scm -1 ) with good electrochemical and mechanical performance. By loading active materials in this basic electrode, more powerful flexible electrodes can be built easily and accurately with the same steps according to the designed proportion. Electrodes constructed according to this method deliver nonnegligible surface capacity (e.g. 1.1 Fcm -2 in surface capacitance, polyaniline/carbon nanotube composite as active materials) with good response, rate performance, excellent durability (10000 times of charge-discharge), and good foldability (1000 times of folding). This pattern of carrier type electrodes provides a simple and universal strategy for manufacturing flexible supercapacitors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Imine-linked covalent organic frameworks (COFs) have received widespread attention because of their structure features such as high crystallinity and tunable pores. However, the intrinsic reversibility of the imine bond leads to the poor stability of imine-linked COFs under strong acid conditions. Also, their thermal stability is significantly lower than that of many other COFs. Herein, we report for the first time that the reversible imine bonds in the skeleton of COFs can be locked through the asymmetric hydrophosphonylation reaction of phosphite. The functionalized COFs not only retain the crystallinity and porous structure but also exhibit evidently improved chemical and thermal stabilities. In addition, the phosphorous acid groups generated by acidic hydrolysis attached to the skeleton endow the COFs with good intrinsic proton conductivity. Due to the diversity of phosphite derivatives and imine-linked COFs, this work may provide an avenue for extending the COF structures and functions through the asymmetric hydrophosphonylation reaction.

In this paper, the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-containing diblock copolymer poly[(p-hydroxybenzaldehyde methacrylate) m -b-(2-((6-oxidodibenzo[c,e][1,2]oxaphosphinin-6-yl)oxy)ethyl methacrylate) n ] (abbrev. poly(HAMA m -b-HEPOMA n )) was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. When it was continued to react with titanium-hybridized aminopropyl-polyhedral oligomeric silsesquioxane (Ti-POSS) through a Schiff-base reaction, new grafted copolymers poly[(Ti-POSS-HAMA) m -b-HEPOMA n ] (abbrev. PolyTi) were obtained. Then, they were used as macromolecular flame retardant to modify epoxy resin materials. The thermal, flame retardant and mechanical properties of the prepared EP/PolyTi composites were tested by TGA, DSC, LOI, UL-94, SEM, Raman, DMA, etc. The migration of phosphorus moiety from epoxy resin composites was analyzed by immersing the composites into ethanol/H 2 O solution and recording the extraction solution by UV-Vis spectroscopy. The results showed that the added PolyTi enhanced the glass transition temperature, the carbon residue, the graphitization of char, LOI, and mechanical properties of the EP/PolyTi composites when compared to pure cured EP. Furthermore, the phosphorus moieties were more likely to migrate from EP/DOPO composites than that from EP/PolyTi composites. Obviously, compared with small molecular flame retardant modified EP, the macromolecular flame retardant modified EP/PolyTi composites exhibited better thermal stability, flame retardancy, and resistance to migration.

Due to unique chelating and macrocyclic effects, crown ether compounds exhibit wide application prospects. They could be introduced into amphiphilic copolymers to provide new trigger mode for drug delivery. In this work, new amphiphilic random polymers of poly(lipoic acid-methacrylate-co-poly(ethylene glycol) methyl ether methacrylate-co- N -isopropylacrylamide-co-benzo-18-crown-6-methacrylamide (abbrev. PLENB) containing a crown ether ring and disulphide bond were synthesized via RAFT polymerization. Using the solvent evaporation method, the PLENB micelles were formed and then used to load substances, such as doxorubicin hydrochloride (DOX) and gold nanoparticles. The results showed that PLENB exhibited a variety of lowest critical solution temperature (LCST) in response to the presence of different ions, such as K + , Na + and Mg 2+ . In particular, the addition of 150 mM K + increased the LCST of PLENB from 31 to 37 °C and induced the release of DOX from the PLENB@DOX assemblies with a release rate of 99.84% within 12 h under 37 °C. However, Na + and Mg 2+ ions could not initiate the same response. Furthermore, K + ions drove the disassembly of gold aggregates from the PLENB-SH@Au assemblies to achieve the transport of Au NPs, which is helpful to construct a K + -triggered carrier system.

This paper rationally designs the morphology and phase structure of carbon nanotube/polyaniline@MoS 2 (CNT/PANI@MoS 2 ) composites, with MoS 2 conductive wrapping growing vertically on the outer layer of the composites via hydrothermal method. The crystalline nature and chemical properties are characterized by X-ray diffraction (XRD), Flourier transformation infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS). Morphology and microstructures are determined by Scanning electric microscopy (SEM), Transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET). The developed composites possess excellent electrochemical properties (the specific capacitance is substantially increased by ~119%, reaching 700.0 F g -1 after wrapping by MoS 2 ) and good cycling stability (after over 5000 cycles retains 80.8% capacitance) in three-electrode systems, which indicating that the unique morphology of MoS 2 shells endow the channels to composites for rapid charge transport and ionic diffusion. Furthermore, symmetric supercapacitors devices assembled with the CNT/PANI@MoS 2 composites achieve specific capacitance of 459.7 F g -1 at 1 A g -1 , capacitance retention is 97.4% after 10,000 cycles and reach superior energy density of 40.9 Wh kg -1 at the power density of 400 W kg -1 . This strategy of three-dimensional wrapping method may open up a new potential to relieve the dilemma of degraded performance of supercapacitor, while improving the capacitance and stability for supercapacitors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Schiff base formation reaction is highly dynamic, and the microstructure of Schiff base polymers is greatly affected by reaction kinetics. Herein, a series of Schiff base cross-linked polymers (SPs) with different morphologies are synthesized through adjusting the species and amount of catalysts. Nitrogen/oxygen co-doped hierarchical porous carbon nanoparticles (HPCNs), with tunable morphology, specific surface area (SSA) and porosity, are obtained after one-step carbonization. The optimal sample (HPCN-3) possesses a coral reef-like microstructure, high SSA up to 1003 m 2 g -1 , and a hierarchical porous structure, exhibiting a remarkable specific capacitance of 359.5 F g -1 (at 0.5 A g -1 ), outstanding rate capability and cycle stability in a 1 M H 2 SO 4 electrolyte. Additionally, the normalized electric double layer capacitance (EDLC) and faradaic capacitance of HPCN-3 are 0.239 F m -2 and 10.24 F g -1 respectively, certifying its superior electrochemical performance deriving from coral reef-like structure, high external surface area and efficient utilization of heteroatoms. The semi-solid-state symmetrical supercapacitor based on HPCN-3 delivers a capacitance of 55 F g -1 at 0.5 A g -1 , good cycle stability of 86.7% after 5000 GCD cycles at 10 A g -1 , and the energy density ranges from 7.64 to 4.86 Wh kg -1 ., (© 2021 IOP Publishing Ltd.)

Although there have been notable advances in adhesive materials, the ability to program attaching and detaching behavior in these materials remains a challenge. Here, we report a borate ester polymer hydrogel that can rapidly switch between adhesive and nonadhesive states in response to a mild electrical stimulus (voltages between 3.0 and 4.5 V). This behavior is achieved by controlling the exposure and shielding of the catechol group through water electrolysis-induced reversible cleavage and reformation of the borate ester moiety. By switching the electric field direction, the hydrogel can repeatedly attach to and detach from various surfaces with a response time as low as 1 s. This programmable attaching/detaching strategy provides an alternative approach for robot climbing. The hydrogel is simply pasted onto the moving parts of climbing robots without complicated engineering and morphological designs. Using our hydrogel as feet and wheels, the tethered walking robots and wheeled robots can climb on both vertical and inverted conductive substrates (i.e., moving upside down) such as stainless steel and copper. Our study establishes an effective route for the design of smart polymer adhesives that are applicable in intelligent devices and an electrochemical strategy to regulate the adhesion., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Stress sensing is the basis of human-machine interface, biomedical engineering, and mechanical structure detection systems. Stress sensing based on mechanoluminescence (ML) shows significant advantages of distributed detection and remote response to mechanical stimuli and is thus expected to be a key technology of next-generation tactile sensors and stress recorders. However, the instantaneous photon emission in ML materials generally requires real-time recording with a photodetector, thus limiting their application fields to real-time stress sensing. In this paper, we report a force-induced charge carrier storage (FICS) effect in deep-trap ML materials, which enables storage of the applied mechanical energy in deep traps and then release of the stored energy as photon emission under thermal stimulation. The FICS effect was confirmed in five ML materials with piezoelectric structures, efficient emission centres and deep trap distributions, and its mechanism was investigated through detailed spectroscopic characterizations. Furthermore, we demonstrated three applications of the FICS effect in electronic signature recording, falling point monitoring and vehicle collision recording, which exhibited outstanding advantages of distributed recording, long-term storage, and no need for a continuous power supply. The FICS effect reported in this paper provides not only a breakthrough for ML materials in the field of stress recording but also a new idea for developing mechanical energy storage and conversion systems., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© The Author(s) 2020.)

Introduction of both nitrogen and transition metal elements into the carbon materials has demonstrated to be a promising strategy to construct highly active electrode materials for energy shortage. In this work, through the coordination reaction between Fe 3+ and 1,3,5-tris(4-aminophenyl)benzene, metallosupramolecular polymer precursors are designed for the preparation of carbon flakes co-doped with both Fe and N elements. The asprepared carbon flakes display wrinkled edges and comprise Fe 3 C nanoparticle and active site of Fe-N x . These carbon materials exhibit excellent electrocatalytic performance. Towards oxygen reduction reaction (ORR), the optimized sample has E onset and E half-wave of 0.93 V and 0.83 V in alkaline system, respectively, which are very close to that of Pt/C. This approach may offer a new way to high performance and lowcost electrochemical catalysts., Competing Interests: Funding: The National Natural Science Foundation of China (51673161, 51773172), Scientific and Technological Innovation Platform of Fujian Province (2014H2006), National Science and Technology Ministry (2014BAF08B03) supported our work.

Hydrogel electrolytes are of particular interest in the fabrication of flexible supercapacitors that are able to withstand deformation and physical damage. Nevertheless, there still exists a huge space in the design of hydrogel electrolytes with comprehensive performances including high processability, conductivity, mechanical strength, and self-healability. Herein, a slidable polymer network is constructed through the cross-linking reaction among commercially available polyethyleneimine (PEI), polyvinyl alcohol (PVA), and 4-formylphenylboronic acid (Bn) to generate PEI-PVA-Bn hydrogels, which have high adaptability to various electrolytes such as LiCl, NaCl, KCl, and ionic liquids. The as formed hydrogel electrolytes not only show excellent mechanical property (elongation at break up to 1223%, strength of 34.6 kPa) and self-healability (highest strain self-healing efficiency reaches 94.3% within 2 min) but also exhibit high conductivity (up to 21.49 mS cm -1 ). Flexible supercapacitors constructed by sandwiching the PEI-PVA-Bn-LiCl hydrogel electrolyte between two multiwalled carbon nanotube electrodes demonstrate a broadened operating potential window of 1.4 V, specific capacitance of 16.7 mF cm -2 , high cycling stability up to 10 000 charge/discharge cycles, and excellent mechanical stability.

In this article, we introduce a pH-responsive charge-reversible and photo-crosslinkable polymer nanoparticle. It is prepared via typical self-assembly from a block copolymer poly((7-(4-vinyl-benzyloxyl)-4-methylcoumarin)-co-acrylicacid)-b-poly((2-dimethylamino) ethyl methacrylate)-co-styrene) (P(VBMC-co-AA)-b-P(DMAEMA-co-St)), whose two blocks have different ionizable moieties. In an aqueous solution of pH ≤ 4, the cationic polymer nanoparticles are formed due to the fully protonated PDMAEMA. At a pH ranging from 5.0 to 7.8, partially ionized PAA and protonated PDMAEMA lead to the formation of polymer nanoparticles with a mixed shell. In a pH range of 8-10, a large amount of precipitation is produced within the isoelectric point (IEP) region because of the weak hydrophilic two blocks. In an aqueous solution of pH ≥ 10, polymer nanoparticles are reformed with PAA shell and P(DMAEMA-co-St) core. The coumarin groups of polymer can undergo photo-crosslinking and photo-cleavage reactions under UV light irradiation at λ = 365 nm and λ = 254 nm, respectively. The reversible nature of the photo-reaction can regulate the reversal of polymer nanoparticles. Furthermore, the aggregation-induced fluorescence emission (AIFE) property of polymer nanoparticles at different pH is tested by fluorescence emission spectra. The results indicate that the aggregation state of coumarin blocks in solution also changes with the pH value. The DOX release experiment in vitro shows that the release behavior of DOX-loaded nanoparticles can be adjusted by pH and light to achieve significant control. The inhibitory effect on the growth of tumor cells is displayed by cellular uptake and cytotoxicity test in vitro . The self-assembly system of polymer nanoparticles can be cooperatively controlled by multiple stimulations and displays potential applications in controlled drug delivery.

An effective method was established for the determination and classification of flammable liquids by headspace gas chromatography-mass spectrometry (HS-GC-MS). The volatile components, equilibrium temperature and equilibrium time of gravure ink were investigated. The volatile components of flammable liquids were identified by comparison with the standard mass spectrum databases, and quantified by the external standard method. The recoveries were in the range of 92.8%-103.1% with the relative standard deviations between 0.88% and 2.88%. The flash points of the samples were calculated by a prediction model and compared with the experimentally measured values. The results showed that the maximum deviation between the predicted and measured flash points was 3.2℃. This method provides a novel, efficient and convenient way for the classification of flammable liquids.

Simultaneous introduction of both transition metal and other inorganic elements into the carbon matrix has attracted great attention in the fabrication of carbon materials with high electrochemical properties. Herein, rational design of ligand-iron coordinative supramolecular precursors is achieved for the fabrication of Fe-N/C catalysts, which possess high oxygen reduction reaction (ORR) performance. A series of precursors are prepared by a simple coordination reaction between a three armed catechol monomer and iron ions. Particular interest is focused on tuning the doping species, surface area and morphology of the Fe-N/C catalysts through a simple selection of iron resources. We show that an Fe-N/C catalyst derived from Fe 2 (SO 4 ) 3 at a carbonization temperature of 800 °C, has the optimized ORR performance with an onset potential of 0.930 V and half-wave potential of 0.801 V. Detailed investigation indicates that the synergistic effect among doping elements of nitrogen and sulfur and the unique carbon structure determines the performance of the Fe-N/C catalysts. Our findings may be of significance for the fabrication of doped carbon materials using coordinative supramolecular polymers as precursors.

Modification of cotton fabric to achieve superhydrophobic, self-cleaning and heat resistance is of particular interest for practical applications. Herein, a simple surface modification route is designed to introduce flame retardant component 9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and low surface energy crosslinked polymer network comprising both fluorine and silicon elements on the surface of cotton fabric. The modified cotton fabric shows characteristic of superhydrophobic property with water contact angle of 154.8°, and exhibits promising self-cleaning performance. With the characters of hydrophobicity and lipophilicity, the modified cotton fabric can efficiently separate oil-water mixture and even emulsion. Moreover, the introduction of DOPO and fluorine-silicon-containing coating not only enhances the heat resistance of cotton, but also improves the flame retardant property., (Copyright © 2018. Published by Elsevier Ltd.)

Core-shell structures are of particular interest in the development of advanced composite materials as they can efficiently bring different components together at nanoscale. The advantage of this structure greatly relies on the crucial design of both core and shell, thus achieving an intercomponent synergistic effect. In this report, we show that decorating semiconductor nanocrystals with a boronate polymer shell can easily achieve programmable core-shell interactions. Taking ZnO and anatase TiO 2 nanocrystals as inner core examples, the effective core-shell interactions can narrow the band gap of semiconductor nanocrystals, change the HOMO and LUMO levels of boronate polymer shell, and significantly improve the carrier density of core-shell particles. The hole mobility of core-shell particles can be improved by almost 9 orders of magnitude in comparison with net boronate polymer, while the conductivity of core-shell particles is at most 30-fold of nanocrystals. The particle engineering strategy is based on two driving forces: catechol-surface binding and B-N dative bonding and having a high ability to control and predict the shell thickness. Also, this approach is applicable to various inorganic nanoparticles with different components, sizes, and shapes.

Stimuli-responsive polymeric systems containing special responsive moieties can undergo alteration of chemical structures and physical properties in response to external stimulus. We synthesized a hybrid amphiphilic block copolymer containing methoxy polyethylene glycol (MePEG), methacrylate isobutyl polyhedral oligomeric silsesquioxane (MAPOSS) and 2-(diisopropylamino)ethyl methacrylate (DPA) named MePEG- b -P(MAPOSS- co -DPA) via atom transfer radical polymerization (ATRP). Spherical micelles with a core-shell structure were obtained by a self-assembly process based on MePEG- b -P(MAPOSS- co -DPA), which showed a pH-responsive property. The influence of hydrophobic chain length on the self-assembly behavior was also studied. The pyrene release properties of micelles and their ability of antifouling were further studied.

A series of novel azobenzene-based amphiphilic random copolymers P(POSSMA- co -AZOMA- co -DMAEMA) were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. A light and reduction dual-responsive azo group, pH-responsive tertiary amine group and super hydrophobic POSS moiety were incorporated into the polymer chain to generate multi-stimuli-responsiveness. Self-assembly of these amphiphilic copolymers led to the formation of spherical micelles in aqueous solution. The light, pH and reduction responsive properties of the micelles were investigated systematically by DLS, TEM, UV-vis, FTIR and NMR. The azo groups can undergo trans - cis isomerization under UV light irradiation, thus causing a diameter change of the micelles. Owing to the large proportion of tertiary amine groups in amphiphiles, these micelles showed sensitive pH-response behavior. The hydrophobic azo pendant in the polymer chain completely reduced to a more hydrophilic substituted aniline in a reductive environment, resulting in the increase of overall hydrophilicity of amphiphiles and the disassembly of polymeric micelles. Owing to these multi-stimuli-responses, the polymeric micelles showed rapid and efficient release properties of hydrophobic molecules in response to pH and reductive stimuli., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Covalently stabilized polymer assemblies are normally fabricated from the self-assembly of polymer chains followed by a cross-linking reaction. In this report, we show that a cross-linking-induced self-assembly approach, in which boronate cross-linking sites are formed by the condensation reaction between boronic and catechol groups, can organize polymer networks into uniform assemblies. Self-assembly of these boronate cross-linked polymer networks adopts two different driving forces in water and methanol solutions. Hydrophobic aggregation of polymer networks in water solution affords spherical assemblies, while B-N dative bond formed between boronate and imine functionalities in methanol solution organizes the polymer networks into bundle-like assemblies. We not only demonstrate the intrinsic stimuli-responsive degradability of these cross-linked assemblies but also show that their degradation can cause a controllable release of guest molecules. Moreover, bundle-like assemblies with rough surface and exposed boronate functionalities exhibit dramatically higher cell penetration capability than the spherical assemblies with smooth surface and embedded boronate functionalities.

To precisely deliver drug molecules at a targeted site and in a controllable manner, there has been great interest in designing a synergistical drug delivery system that can achieve both surface charge-conversion and controlled release of a drug in response to different stimuli. Here we outline a simple method to construct an intelligent drug carrier, which can respond to two different pH values, therefore achieving charge conversion and chemical-bond-cleavage-induced drug release in a stepwise fashion. This drug carrier comes from the self-assembly of a block copolymer-DOX conjugate synthesized through a Schiff base reaction between poly(2-(diisopropylamino)ethyl methacrylate-b-poly(4-formylphenyl methacrylate-co-polyethylene glycol monomethyl ether methacrylate) (PDPA-b-P(FPMA-co-OEGMA)) and DOX. The surface charge of the BCP-DOX micelles reversed from negative to positive when encountering a weakly acidic environment due to the protonation of PDPA segments. In vitro cellular uptake measurement shows that the cellular uptake and internalization of the BCP-DOX micelles can be significantly enhanced at pH ∼ 6.5. Moreover, this drug carrier exhibits a pH-dependent drug release owing to the cleavage of the imine bond at pH < 5.5. With this dual-pH responsive feature, these micelles may have the ability to precisely deliver DOX to the cancer cells.

Exploitation of facile and versatile synthetic approaches to polymeric nanoarchitectures is of great interest in polymer science and engineering. Herein, we show that a simple hydrothermal route using double-solvents as reaction media has the ability to generate polymer nanospheres with tunable morphologies and components. In this one-pot approach, condensation polymerization of a resol precursor and radical polymerization of styrene are allowed to occur simultaneously under hydrothermal treatment. The synergistic self-organization of phenol-formaldehyde crosslinked networks and polystyrene chains leads to the formation of well-defined hollow nanospheres with adjustable shell thickness or even Janus particles comprising a solid hemisphere and a hollow hemisphere. Furthermore, control over the composition of the hollow polymer nanospheres can be easily achieved by introducing a third monomer into the hydrothermal system.

The use of reversible linkers in polymers has been of interest mainly for biomedical applications. Herein, we present a novel strategy to utilize reversible interactions in polymeric nanoparticles to generate hollow metal-organic nanoparticles (MOPs). These hollow MOPs are synthesized from self-assembled polymeric nanoparticles using a simple metal-comonomer exchange process in a single step. The control over the size of the polymer precursor particles translates into a straightforward opportunity for controlling MOP sizes. The shell thickness of the MOPs could be easily tuned by the concentration of metal ions in solution. The underlying mechanism for the formation of these hollow MOPs has been proposed. Evidence for the generality of the method is provided by its application to a variety of metal ions with different coordination geometries., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Intermolecular B-N coordination has been recognized as a promising driving force for molecular self-organization. However, direct utilization of this intermolecular interaction as building bridge for the supramolecular self-assembly of chemical functionalities to form nano-sized architectures remains a daunting challenge. Here, we outline a multiple intermolecular B-N coordination based supramolecular system, where small boronate molecules can be brought together in solution to form nanoparticles with controllable sizes and morphologies. We not only demonstrate the intrinsic switchable fluorescence and the stimuli-responsive capabilities of the designed boronate molecule, but also show that the stabilized or surface functionalized nanoparticles are degradable in response to pH and D-glucose and able to retain the fluorescence features of the boronate molecule. Additionally, the degraded nanoparticles can repair themselves through the reformation of B-N coordination.

The design of nanoscale drug delivery systems for the targeted codelivery of multiple therapeutic drugs still remains a formidable challenge (ACS Nano, 2013, 7, 9558-9570; ACS Nano, 2013, 7, 9518-9525). In this article, both mitomycin C (MMC) and methotrexate (MTX) loaded DSPE-PEG micelles (MTX-M-MMC) were prepared by self-assembly using the dialysis technique, in which MMC-soybean phosphatidylcholine complex (drug-phospholipid complex) was encapsulated within MTX-functionalized DSPE-PEG micelles. MTX-M-MMC could coordinate an early phase active targeting effect with a late-phase synergistic anticancer effect and enable a multiple-responsive controlled release of both drugs (MMC was released in a pH-dependent pattern, while MTX was released in a protease-dependent pattern). Furthermore, MTX-M-MMC could codeliver both drugs to significantly enhance the cellular uptake, intracellular delivery, cytotoxicity, and apoptosis in vitro and improve the tumor accumulation and penetration and anticancer effect in vivo compared with either both free drugs treatment or individual free drug treatment. To our knowledge, this work provided the first example of the systemically administrated, orthogonally functionalized, and self-assisted nanoscale micelles for targeted combination cancer chemotherapy. The highly convergent therapeutic strategy opened the door to more simplified, efficient, and flexible nanoscale drug delivery systems.

Polymer assemblies with good biocompatibility, stimuli-responsive properties and clinical imaging capability are desirable carriers for future biomedical applications. Herein, we report on the synthesis of a novel anthracenecarboxaldehyde-decorated poly(N-(4-aminophenyl) methacryl amide-oligoethyleneglycolmonomethylether methacrylate) (P(MAAPAC-MAAP-MAPEG)) copolymer, comprising fluorescent chromophore and acid-labile moiety. This copolymer can assemble into micelles in aqueous solution and shows a spherical shape with well-defined particle size and narrow particle size distribution. The pH-responsive property of the micelles has been evaluated by the change of particle size and the controlled release of guest molecules. The intrinsic fluorescence property endows the micelles with excellent cell/tissue imaging capability. Cell viability evaluation with human hepatocellular carcinoma BEL-7402 cells demonstrates that the micelles are nontoxic. The cellular uptake of the micelles indicates a time-dependent behavior. The H22-tumor bearing mice treated with the micelles clearly exhibits the tumor accumulation. These multi-functional nanocarriers may be of great interest in the application of drug delivery.

In the present study we have investigated novel MTX prodrug-targeted and MMC-loaded PLA-lipid-PEG hybrid NPs. These employ a double emulsion solvent evaporation method for the introduction of an anticancer drugs moiety of the MMC-soybean phosphatidylcholine complex or DSPE-PEG-MTX, in which the MTX prodrug can be exploited as a targeting ligand. The prepared drug delivery systems present a spherical shape, a small particle size (219.6 ± 2.1 nm) with narrow particle size distribution, high MMC encapsulation efficiency (90.5 ± 3.0%) and a sustained and pH-controlled MMC release. The advantage of the new drug delivery systems is that the two-anticancer drug moiety can coordinate the early-phase targeting effect with the later-phase anticancer effect. In vivo pharmacokinetics, following intravenous administration of the drug delivery systems, indicates a prolonged systemic circulation time of MMC. More importantly, the drug delivery systems exhibited a significant accumulation of MMC in the nuclei as the site of MMC action, which was indicative of the enhancement of anticancer activity. Such a design of drug delivery systems may open up a new horizon for targeted delivery and sustained and controlled release of MMC.

This paper introduces not only a simple hydrothermal route to silver-polyaniline (Ag-PANI) nanocomposites with controllable morphology, but also a type of catalyst possessing tunable and switchable catalytic capability. Ag-PANI Janus nanoparticles (NPs) and Ag@PANI core-shell NPs have been constructed successfully at different hydrothermal temperatures. The diameter of both Ag and PANI hemispheres of Janus NPs, as well as the PANI shell thickness of core-shell NPs, was finely tuned via adjustment of the feed ratio. We also gained a deeper insight into the functionalities of PANI components in the catalytic capability of the heterogeneous catalysts, choosing catalytic reductions of nitrobenzene (NB) and 4-nitrophenol (4-NP) as model reactions. Our results showed that the catalytic capability of the nanocomposites was dependent on the PANI morphology and hydrophobicity. The PANI shell coating on Ag NPs can concentrate the lipophilic NB, thus leading to an enhanced catalytic capability of Ag@PANI core-shell NPs. However, this enhanced catalytic capability was not observed for Ag-PANI Janus NPs when catalytically reducing NB. More importantly, the catalytic capability of the core-shell NPs in the reduction of hydrophilic 4-NP is switchable by varying the PANI shell from an undoped to a doped state.

Core-shell nanospheres (CSNSs) with hydrophobic cores and hydrophilic shells were fabricated via a simple mini-emulsion polymerization for the stabilization of platinum nanoparticles (Pt-NPs). The CSNSs showed extremely high loading capacity of Pt-NPs (the largest loading amount of the Pt-NPs was about 49.2 wt%). Importantly, the Pt-NPs/CSNSs nanocomposites had unexpected stability in aqueous solution. DLS results revealed that the CSNSs loaded with Pt-NPs exhibited almost no aggregation after standing for a long time . However, the Pt-NPs immobilized on the CSNSs were not straitlaced: they could transport and redistribute between CSNSs freely when the environmental temperature was higher than the melting point of the CSNS shell. Owing to their excellent stability in aqueous solution, the surface of the Pt-NPs/CSNSs nanocomposites could be further decorated easily. For example, polyaniline (PANI)-coated Pt-NPs/CSNSs, nickel (Ni)-coated Pt-NPs/CSNSs and PANI/Pt-NPs dual-layer hollow nanospheres were facilely fabricated from the Pt-NPs/CSNS nanocomposites.

The organic surfactant template method has been widely used for the preparation of CuO nanorods, nanotubes and nanowires. However, the surfactants in this system have no effect on the properties of the final products because they are flushed away. In this work, we used this method to synthesize a novel type of inorganic-organic hybrid nanowire via the hybridization between CuO and amphiphilic oligomer octadecyl, polyethylene glycol di-butenetrioate (O-B-EG-B). Here O-B-EG-B, as a structure director, was not flushed away but remained in the prepared hybrid nanowires because it was bound around CuO or entrapped in interior CuO. The hybrid nanowires showed CuO cores and P(O-B-EG-B) shells when the concentration of O-B-EG-B was 0.4 mg ml(-1), but exhibited P(O-B-EG-B) cores and CuO shells when the concentration of O-B-EG-B was 4.0 mg ml(-1). We found that the hybrid nanowires with P(O-B-EG-B) cores and CuO shells could sense a slight change in the relative humidity (RH) and respond by rapidly changing their conductivity. The resistance changed by about two orders of magnitude within the humidity range from 5% to 83.8%. Moreover, a humidity sensor based on this type of nanowire not only showed long-term stability but also exhibited excellent reversibility to moisture changes in air.