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Excellent radiation resistance is a prerequisite for pressure-sensitive hydrogels to be used in high-energy radiation environments. In this work, tannic acid-modified boron nitride nanosheet (BNNS-TA) is first prepared as the radiation-resistant additive by a facile one-step ball milling of hexagonal boron nitride and tannic acid. Then, polyacrylamide (PAAm)-based pressure-sensitive hydrogel doped with BNNS-TA and Fe3+ ions is fabricated. The ternary BNNS-TA/Fe3+/PAAm hydrogel exhibits excellent compressive strength (at least four times the compressive strength of unfilled pure PAAm hydrogel), pressure-sensitive performance (gauge factor is up to 1.4), and performance recovery due to the combination of multiple intermolecular interactions, such as covalent crosslinking, hydrogen bonds, and ion coordination interactions. The BNNS-TA/Fe3+/PAAm hydrogel can be made as a pressure sensor installed in the control circuit or attached on the human body to detect human activities accurately. More importantly, the compressive strength and the pressure-sensitive performance of the BNNS-TA/Fe3+/PAAm hydrogel can be maintained after the hydrogel is irradiated by 60Co gamma-ray at an absorbed dose of 15 kGy. As a comparison, the compressive strength of the unfilled PAAm hydrogel is only a quarter of that before irradiation. This work not only reveals a facile method to achieve the preparation of chemically modified BNNS as a promising radiation-resistant additive but also provides a novel strategy for the development of pressure-sensitive hydrogel devices in radiation environments.

The design of pore structure is the key factor for the performance of porous carbon spheres. In this work, novel micron-sized colloidal crystal microspheres consisting of fibrous silica (F-SiO2) nanoparticles are firstly prepared by water-evaporation-induced self-assembly of F-SiO2 nanoparticles in the droplets of an inverse emulsion system to be used as sacrificial templates. Acrylonitrile (AN) was infiltrated in the voids of the F-SiO2 colloidal crystal microspheres, and in-situ induced by 60Co γ-ray to polymerize into polyacrylonitrile (PAN). After the PAN-infiltrated F-SiO2 colloidal crystal microspheres were carbonized and etched with HF solution, novel micron-sized inverse-opal N-doped carbon (IO-NC) microspheres consisting of hollow carbon nanoparticles with a hierarchical macro/meso-porous inner surface were obtained. The IO-NC microspheres have a specific surface area as high as 266.4 m2/g and a molar ratio of C/N of 5. They have a good dispersibility in water, and show a high adsorption capacity towards rhodamine B (RhB) up to 137.28 mg/(g microsphere). This work offers a way to obtain novel micron-sized hierarchical macro/meso-porous N-doped carbon microspheres, which opens a new idea to prepare high-performance hierarchical porous carbon materials.

Solar-driven interfacial steam generation is a promising technique for clean water production because it can minimize thermal loss by localizing solar-to-heat conversion at the air/liquid interface. Here we report an integrated solar evaporator by partially growing 2D polypyrrole microsheets within a melamine foam through chemical vapor polymerization. These microsheets can induce multiple light reflections within the foam, enable omnidirectional light absorption, provide abundant surfaces to promote heat transfer, and achieve spatially defined hydrophobicity to facilitate vapor escape. Meanwhile, the inherent hydrophilicity of the bottom part of the foam promotes spontaneous upward water transport and suppresses heat loss. The composite foam exhibits an excellent apparent evaporation rate of ∼2 kg/(m

The efficient exfoliation of hexagonal boron nitride (h-BN) to fabricate boron nitride nanosheets (BNNS) is a challenging task in the popular field of two-dimensional material preparation. In this paper, a new radiation-induced reduction-exfoliation method is introduced to achieve the one-step exfoliation of h-BN to form Ni-nanoparticle-(NiNP)-bound BNNS (Ni/BNNS) in a binary isopropanol/water medium using gamma-ray radiation at ambient temperature and pressure. The process involves the effective intercalation of Ni2+ ions into h-BN interlayers dispersed in the isopropanol/water medium, followed by the in situ growth of NiNPs under gamma-ray irradiation. Taking advantage of the volume expansion effect generated by the growth of the NiNPs and with help from a cationic surfactant, such as hexadecyltrimethylammonium chloride (CTAC), sheet-like Ni/BNNS in 200 nm squares and with an average BNNS thickness of less than 5 nm can be peeled from h-BN and stably dispersed in water. The prepared magnetic Ni/BNNS exhibits good catalytic performance, excellent structural stability, and reusability toward the reduction of 2-nitroaniline (2-NA). After 5 cycles, the conversion of 2-NA still reaches 95.9% within 500 s. More interestingly, when Ni/BNNS was dispersed in water/methanol solution at a content of 0.17 mg mL−1 followed by exposure to simulated sunlight irradiation, H2 evolution of 8404.3 μmol gNi−1 within 2 h can be detected. This work not only provides a new idea for realizing the exfoliation of layers of nanoscale sheets from h-BN, but it also opens a new route to the one-step preparation of two-dimensional-material-supported nanometal catalysts by taking advantage of gamma-ray radiation.

The combination of the molecular imprinting technology and porous materials is a promising way to obtain high-efficient selective adsorption and separation materials for bioactive macromolecules. In this work, we developed a novel approach to prepare near-infrared (NIR)-light-response inverse-opal lysozyme (Lyz)-imprinted polydopamine/polypyrrole (IO-PDA/PPy-MIP) composite microspheres using micron-sized SiO2 colloidal crystal microspheres as the sacrificed template. The pore size of the IO-PDA/PPy-MIP microspheres can be tuned from 200 to 800 nm by the size of silica nanoparticles which self-assemble to form the template SiO2 colloidal crystal microspheres. The IO-PDA/PPy-MIP microspheres show a rapid selective adsorption ability for Lyz due to the inverse-opal macroporous structure. The adsorption capacity exceeds 800 mg/g within 20 min, and the imprinting factor is as high as 24. The bound Lyz molecules can be released rapidly from IO-PDA/PPy-MIP microspheres triggered by the irradiation of NIR laser and remain enough bioactivity to decompose Escherichia coli efficiently. The prepared IO-PDA/PPy-MIP microspheres also exhibit excellent structure stability and good recyclability. The adsorption capacity can remain up to 90% of the initial value after 5 times recycle. This work provides not only a method to prepare novel NIR-light-response inverse-opal macroporous molecularly imprinted microspheres, but also a new perspective on the design of selectively separation materials for the fast, high-efficient recognition and separation of biomacromolecules.

Composite photocatalysts composed of semiconductor and magnetic matters are of great concern due to their excellent catalytic and recyclable performances. In this work, Fe 3O4 nanoparticles are modified by a fibrous mesoporous silica layer (F-SiO 2), on which a mesoporous Bi2WO6 shell is grown in situ through hydrothermal reaction . Along with the formation of Bi 2WO6 shell, the F-SiO2 layer fades away by the acid etching. As a result, novel spherical core-shell mesoporous Fe3O4@Bi2WO6 nanoparticles with a high BET surface area of 127.3 m2/g are fabricated. The photocatalytic decomposition of methylene blue (MB) under visible light irradiation reveals that the mesoporous Fe3O4@Bi2WO6 nanoparticles show excellent physisorption and photocatalytic performances. The total removal ratio of MB can be achieved as high as 98%. Furthermore, the mesoporous Fe3O4@Bi2WO6 nanoparticles maintain high photocatalytic activity after five cycles. This work provides a new way to construct recyclable mesoporous Bi2WO6 -based nanomaterials with high performance to remove organic pollutants.

Enzyme-based anticancer therapy is more attractive for the less side effect than conventional chemotherapy. However, the poor stability and low membrane permeability of enzymes during the intracellular delivery are constraints for its practical applications. In this work, we synthesized novel near-infrared (NIR)-responsive core–shell-structured Prussian blue@fibrous SiO2 (PBFS) nanoparticles as the carrier of superoxide dismutase (SOD) and a glutathione (GSH)-activated Fenton reagent (DiFe). The PBFS nanoparticles are further modified with a GSH-responsive cationic polymer (poly(2-(acryloyloxy)-N,N-dimethyl-N-(4-(((2-((2-(((4-methyl-2-oxo-2H-chromen-7-yl)carbamoyl)oxy)ethyl)disulfaneyl) ethoxy)carbonyl)amino)benzyl)ethan-1-aminium, PSS) containing disulfide bonds and fluorophores. After SOD and DiFe are loaded on the PBFS-PSS nanoparticles, dual chemodynamic/photothermal therapeutic nanoparticulate systems (PBFS-PSS/DiFe/SOD) are obtained. In vitro experiments show that PBFS-PSS/DiFe/SOD nanoparticles have good biocompatibility and can be tracked under fluorescence microscope during the intracellular delivery process in MCF-7 tumor cells due to the GSH-activated release of fluorophores. They also exhibit high efficiency in NIR photothermal conversion and GSH-activated Fenton reaction in tumor cells, thus achieving high-efficient killing effect of tumor cells based on the combination of photothermal and chemodynamic therapeutic performance (PTT and CDT). This work offers a novel pathway to construct a visual multifunctional nanomedicine platform for future cancer therapy.

The fabrication of polymeric microspheres with a tailored hierarchically porous structure has great practical significance although it has been a longstanding challenge. Herein, we report a novel method to construct hierarchically porous microspheres with inner macropores and a mesoporous wall (Macro@Meso-SPS) through two consecutive phase separation processes, i.e., swelling-osmosis and polymerization-induced phase separation (PIPS) in solid sulfonated polystyrene (SPS) seed microspheres which were prepared by the sulfonation of polystyrene (PS) microspheres synthesized via γ-ray-radiation-initiated dispersion polymerization with polyvinylpyrrolidone (PVP) as a stabilizer. As PVP is less radiation-stable and more hydrophilic than PS, PVP macromolecular radicals produced under the radiation chemistry effect slightly crosslinked the surface of PS microspheres. A polyporous structure was fabricated through a swelling-osmosis process inside the seed SPS microspheres, and a mesoporous wall was constructed via the PIPS process in the crosslinked shell using methyl methacrylate (MMA) as a secondary monomer. The pore size of the Macro@Meso-SPS microspheres could be tuned from 3.1 to over 50 nm by adjusting the absorbed dose during the synthesis of PS microspheres, the amount and the conversion of MMA in PIPS. The Macro@Meso-SPS microspheres with surface mesopores around 3.1 nm showed better controlled-release performance of the loaded small molecules like methyl orange, whose cumulative release ratio was merely 45.3% after 24 h, compared to those with larger surface pores above 11.2 nm. This work not only provides a new way to construct hierarchically macro-@mesoporous polymer microspheres, but also proves that radiation-initiated polymerization may be a versatile synthetic platform for porous polymer materials with a bespoke structure for various applications like sustained release.

Plasmonic metal nanostructures have attracted considerable attention for solar energy harvesting due to their capability in photothermal conversion. However, the narrow resonant band of the conventional plasmonic nanoparticles greatly limits their application as only a small fraction of the solar energy can be utilized. Herein, a unique confined seeded growth strategy is developed to synthesize black silver nanostructures with broadband absorption in the visible and near-infrared spectrum. Through this novel strategy, assemblages of silver nanoparticles with widely distributed interparticle distances are generated in rod-shaped tubular spaces, leading to strong random plasmonic coupling and accordingly broadband absorption for significantly improved utilization of solar energy. With excellent efficiency in converting solar energy to heat, the resulting black Ag nanostructures can be made into thin films floating at the air/water interface for efficient generation of clean water steam through localized interfacial heating.

The electrochemical property of electrode materials greatly depends on their morphologies. This report introduces a novel and facile synthesis method for polyaniline (PANI) nanotubes from one-step synergistic polymerization of aniline and acrylic acid in an aqueous solution induced by the addition of ammonium persulfate (APS). The molar ratio of aniline to AA ( $X_{\rm{ani/AA}}$ ) is found to have great influence on the morphology of the produced PANI. Hollow PANI nanotubes with an average inner diameter of 80 nm and outer diameter of 180 nm can be mainly produced when $X_{\rm{ani/AA}}$ is not higher than 1. The electrochemical properties of the prepared PANI nanotubes have been investigated using a three-electrode system. The specific capacitance of PANI nanotubes can reach 436 F/g at a current density of 0.5 A/g in 1 mol/L H $_2$ SO $_4$ solution. Furthermore, the specific capacitance of the PANI nanotube maintains 89.2% after 500 charging/discharging cycles at a current density of 0.5 A/g, indicating a good cycling stability.

Finding and exploiting safe and high-efficiency gene carriers have always been critical tasks for gene therapy. In this work, novel GSH-triggered degradable organosilica nanoparticles grafted with guanidinated-fluorinated α-polylysine (o-SiNP-GF) are prepared to be studied as gene carriers. The organosilica matrix of o-SiNP-GF is synthesized through the hydrolysis and condensation of 1,2-bis(triethoxysilyl)ethane (BTSE) and bis[3-(triethoxysilyl)propyl]tetrasulfide (BTSPTS). The o-SiNP-GF nanoparticles have a size of about 20 nm. They possess a positive zeta potential of 42 mV in PBS (pH 7.4) and can be disintegrated in the presence of GSH. The cytotoxicity and DNA-binding ability of o-SiNP-GF, as well as in vitro gene transfection performance of DNA/o-SiNP-GF complexes, have been investigated using enhanced green fluorescent protein plasmid (pEGFP) as the DNA model. MTT assay shows that the cytotoxicity of o-SiNP-GF is very low even at a concentration up to 800 μg mL-1. The o-SiNP-GF nanoparticles can effectively bind to pEGFP through a complex coacervation method. The in vitro transfection efficiency of pEGFP/o-SiNP-GF complexes in 293T cells is up to 94.7% at the N/P ratio of 10, much higher than that of pEGFP/PEI complexes. Luciferase gene and fibroblast growth factor (FGF2) gene are also used as the DNA models to study the in vivo gene transfection performance of the o-SiNP-GF carrier by bioluminescence imaging and the evaluation of the healing rate of a mouse wound, respectively. Compared with naked DNA and DNA/PEI complexes, DNA/o-SiNP-GF complexes show much higher in vivo transfection efficiency. This work not only provides a way to prepare novel GSH-triggered degradable organosilica nanoparticles of size less than 50 nm, but also proves that the modification of guanidinated-fluorinated α-polylysine is an effective method to improve the efficiency of gene carriers.

In this article, the stability of a classic emulsion and a mini-emulsion composed of water, styrene (St) and sodium dodecyl sulfate (SDS) during the freezing process in liquid nitrogen and refrigerator (−20 °C) respectively was studied. Creaming appeared in the classic emulsion and mini-emulsion during the freezing process in refrigerator, however, no lamination was observed in any emulsions during their freezing process in liquid nitrogen. The polymerization of St monomer in frozen emulsions by liquid nitrogen freezing was then initiated by γ-ray radiation at −5 °C. The inner phase structure of both frozen classic emulsion and mini-emulsion would experience a change from an O/W emulsion to a W/O/W multiple emulsion during the polymerization process, and finally, multi-hollow polystyrene microspheres with a diameter of about 1–20 μm were fabricated. This article provides not only a new idea to develop the low-temperature polymerization technique, but also a simple and green new method to prepare porous polymeric microspheres.

The research on the properties of graphene oxide (GO) in various media has become one of the hottest topics since GO is now the main raw material for graphene-based advanced materials. In this work, the γ-ray radiation chemistry effect of GO nanosheets and their self-aggregation behavior in t-butanol/water medium were investigated. The results show that GO nanosheets are reduced and hydroxyalkylated simultaneously by the alcohol free radicals produced by the radiolysis of t-butanol/water solution under γ-ray radiation. The radiation-modified GO nanosheets will self-assemble into a self-standing graphene hydrogel when the pH of the solution is lower than 2. A hydroxyl-functionalized free-standing graphene aerogel is further obtained simply by freeze-drying. This work provides not only a general self-assembly mechanism of GO nanosheets in strong acidic alcohol/water media under high energy radiation, but also a facile and economical preparation method for hydroxyalkylated graphene-based aerogel.

The development of novel high-performance electrode materials has become increasingly urgent due to the broad demands on the large-capacity energy storage devices nowadays. In this work, cagelike porous sulfonated polystyrene (cSPS) microspheres are first synthesized as the skeleton structure templates, on which polyaniline (PANI) nanoparticles with a size of about 30 nm are loaded through the in situ polymerization of aniline. The novel cSPS-supported PANI composite microspheres (cSPS@PANI) possess hierarchical meso-/macroporous structure, and their BET specific surface area and pore volume reach the maximum at a moderate PANI mass fraction. The electrochemical performance of cSPS@PANI composite microspheres was evaluated through a three-electrode system with 1 M H2SO4 as the electrolyte. The specific capacitance of the cSPS@PANI composite microspheres can reach as high as 374 F g−1 at a current density of 1 A g−1, and only 11.8% is lost after 500 charge/discharge cycles. Thus, the cSPS@PANI composite microspheres can be potentially used as one of the novel outstanding electrode materials in the fabrication of high-performance energy storage devices.

The subtle control on the self-assembly behavior of graphene oxide (GO) nanosheets is one of effective ways for the preparation of high-performance macroscopic graphene-based materials. In this work, detailed characterizations and discussion on the morphological and compositional changes on the solid products in various alcohol-water dispersions of GO under γ-ray radiation were carried out, proving the concurrent hydroxyalkylation and reduction processes of GO nanosheets in the system, which triggered the spontaneous self-assembly of the hydroxyalkylated and reduced GO nanosheets (HA-rGO). The pH and the volume ratio of alcohol to water (ϕ a/w ) are the key factors to control the self-assembly of the HA-rGO sheets. A free-standing graphene hydrogel (GH) only forms in the strong acid alcohol-water media with an appropriate ϕ a/w . After the freeze-drying of the GH, a macroporous graphene aerogel (GA) was obtained, which exhibited a high absorption performance for not only nonpolar molecules (cyclohexane and kerosene), but also most polar molecules (toluene, chloroform, glycol, etc). This work demonstrates a comprehensive self-assembly mechanism of GO nanosheets in an aqueous media under γ-ray radiation and reveals that GA produced from the reduction of GO can be used as potential super-adsorbents for not only waste oil, but also the polar alcohols.

Improving the radiation resistance of epoxy resin (EP) is pivotal for the reliability of equipment and the safety of facilities in the nuclear industry. Hexagonal boron nitride (h-BN) is attractive in the preparation of radiation-resistant materials due to its good radiation stability and neutron shielding capability. In this work, h-BN/EP composites with enhanced radiation resistance were fabricated by solution blending. The tensile strength and thermal properties of the composites after γ-ray and neutron irradiation were investigated. The results showed that the addition of h-BN improved the mechanical property and the glassy transition temperature of the resin. The presence of low-level h-BN was favorable to enhance the radiation resistance of EP. As for composites with the 0.05% mass percentage of h-BN, the absorbed dose required to decrease relative tensile strength by 50% was about 300 kGy, which was higher than that of neat EP. The intrinsic mechanism of radiation resistance was attributed to the oxygen barrier effect as investigated by XPS and EPR. Then, benefiting from the absorbing neutrons capability of boron atoms, an addition of 0.55% h-BN to the EP resin could reduce the neutron transmittance of the resin by 5.6%. This study demonstrates that the blending with h-BN can increase the radiation-resistant property of EP resin, meanwhile augmenting the neutron shielding ability.

The creation of high surface area and effective active sites is the key problem for the synthesis of high-performance porous carbon materials. In this work, polyacrylonitrile-coated fibrous silica (F-SiO2@PAN) microspheres were prepared by in situ polymerization of acrylonitrile on fibrous mesoporous silica microspheres induced by γ-ray radiation. After F-SiO2@PAN microspheres were carbonized and etched with hydrofluoric acid, uniform fibrous N-doped porous carbon (FNC) microspheres with an average size of 286 nm and a molar ratio of C/N of 5.2 were successfully prepared. As revealed by TEM, SEM, and N2 adsorption-desorption isotherms analysis, FNC microspheres have a hierarchal micro-macroporous structure with a particular high surface area of 554.5 m2/g. The FNC microspheres also exhibit a good water dispersibility and an excellent adsorption ability to rhodamine B in water. The equilibrium adsorption capacity of FNC microspheres could reach 95.4 mg/g, which is 1.6 times as that of the primary silica template microspheres. The adsorption kinetics and thermodynamics of FNC microspheres are in accord with the pseudo-second-order kinetic equation and Freundlich isotherm model, respectively. This work provides a facile synthesis method for novel N-doped hierarchical micro-macroporous carbon microsphere as a potential high-performance adsorbent material.

Chitosan (CS) is expected to be an ideal gene carrier for its high biosafety. In this work, CS with low molecular weight were prepared through the γ-ray radiation on the acetic acid solution of CS. The CS chains were scissioned under the γ-ray radiation, and the molecular weight (MW) of CS decreased with the absorbed dose. When the absorbed dose was above 30 kGy, the molecular weight of CS decreased about an order of magnitude. The γ-ray-radiation-scissioned CS can e ectively bind with plasmid (pEGFP) through complex coacervation method, forming pEGFP/ γ-ray-radiation-scissioned CS complex particles with a size of 200-300 nm. The complex particles have good stability and little cytotoxicity. The in uitro gene transfection efficiencies of the pEGFP/ γ-ray-radiation-scissioned CS complex particles were investigated by fluorescence microscope and flow cytometry. The results showed that the gene vectors using γ-ray-radiation-scissioned CS as the carrier will possess better gene transfection efficiency than those using natural high-MW CS as the carrier. The higher the absorbed dose, the smaller the MW of CS and the better transfection efficiency of the corresponding gene vector. This work provides a green and simple method on the preparation of CS-based gene vectors with high efficiency and biosafety.

Recent advances in the research on the molecular mechanism of cell death and methods for preparation of nanomaterials make the integration of various therapeutic approaches, targeting, and imaging modes into a single nanoscale complex a new trend for the development of future nanotherapeutics. Hence, a novel ellipsoidal composite nanoplatform composed of a magnetic Fe3O4/Fe nanorod core (~120 nm) enwrapped by a catalase (CAT)-imprinted fibrous SiO2/ polydopamine (F-SiO2/PDA) shell with thickness 70 nm was prepared in this work. In vitro experiments showed that the Fe3O4/Fe@F-SiO2/PDA nanoparticles can selectively inhibit the bioactivity of CAT in tumor cells by the molecular imprinting technique. As a result, the H2O2 level in tumor cells was elevated dramatically. At the same time, the Fe3O4/Fe core released Fe ions to catalyze the conversion of H2O2 to ·OH in tumor cells. Eventually, the concentration of ·OH in tumor cells rapidly rose to a lethal level thus triggering apoptosis. Combined with the remarkable near-infrared light (NIR) photothermal effect of the CAT-imprinted PDA layer, the Fe3O4/Fe@F-SiO2/PDA nanoparticles can effectively kill MCF-7, HeLa, and 293T tumor cells but are not toxic to nontumor cells. Furthermore, these nanoparticles show good capacity for magnetic targeting and suitability for magnetic resonance imaging (MRI). Therefore, the integrated multifunctional nanoplatform opens up new possibilities for high-efficiency visual targeted nonchemo therapy for cancer.

Self-healable polyacrylamide-based hydrogels were prepared at room temperature via a one-step emulsion copolymerization of acrylamide (AM), dodecyl 2-methacrylate (DM), and 5-acetylaminopentyl acrylate (AAPA) using sodium dodecyl sulfonate (SDS) as the emulsifier and ammonium persulfate (APS) as the initiator. The produced linear multi-block copolymer chains are composed of randomly-linked hydrophilic polyacrylamide segments (PAM) and hydrophobic segments constituted by DM and AAPA units (P(DM-co-AAPA)). The P(DM-co-AAPA) segments will self-aggregate into hydrophobic microdomains during the polymerization process driven by the hydrophobic interactions, and finally separate from water phase, acting as the crosslinks and leading to the formation of strong hydrogels with a storage modulus as high as 400 Pa. These hydrophobic microdomains will be dissolved in water when the temperature increases to 70 °C, resulting in a temperature-responsive reversible sol-gel transition of the prepared hydrogels. Furthermore, the prepared hydrogels have excellent self-healing ability. The broken hydrogels can be automatically healed into a body with a same strength within 2-min’s contact. This work provides a new simple way to prepare reversible physical crosslinked hydrogel with high strength and self-healing efficiency.

Excellent mechanical strength is critical for polymer hydrogels to be successfully applied in the field of mechanical devices and tissue engineering scaffolds. Herein, novel nanoparticle-reinforced polyacrylamide-based hydrogel with high mechanical strength was designed and successfully prepared in this work through the RAFT polymerization of acrylamide (AM) and ethylene glycol dimethacrylate (EGDMA) in the presence of particulate macro-RAFT agents in water. Amphiphilic poly(acrylic acid)-b-polystyrene (PAA-b-PS) copolymer was first synthesized via RAFT copolymerization in methanol. Then the vesicles of about 200 nm in size and decorated with RAFT groups were formed by the self-assembly of PAA-b-PS copolymers during the water dialysis, which can be considered as particulate macro-RAFT agents. After the addition and the polymerization of EGDMA and AM monomers in order, hydrogel filled with uniformly distributed PAA-b-PS nanoparticles was in situ formed, showing an extraordinary compression strength and tensile strength up to 7.0 MPa and 2.0 MPa, respectively, as well as an excellent fatigue resistance under loading–unloading. The self-reinforcement effect of the PAA-b-PS nanoparticles should be related to the strong interaction originating from the chemical and hydrogen bonds between the particulate macro-RAFT agents and polyacrylamide chains. This work provides not only a novel method for macro-RAFT agents, but also opens a new feasible strategy to prepare high-performance hydrogels reinforced by polymeric nanoparticles.

The development of gene carriers with high delivery efficiency and enough biosafety to replace the current viral vectors and cationic liposomes has long been a key project to achieve the practical application of gene therapy. As an abundant natural polymer, chitosan (CS) possesses incomparably high biocompatibility. However, when it is used as a gene carrier, the gene transfection efficiency is rather disappointing. Herein, we prepared a novel chitosan derivative, poly(tributyl-(4-vinylbenzyl)phosphonium)-grafted CS (CS-P), via γ-ray radiation-induced grafting copolymerization of tributyl-(4-vinylbenzyl)phosphonium in an acidic solution of CS. The CS-P could combine with pEGFP through a complex coacervation method to form pEGFP-loaded CS-P complex particles with a size of about 150 nm and a high positive zeta potential of 41.7 ± 6.1 mV. Agarose gel electrophoresis and an MTT assay show that the pEGFP-loaded CS-P particles have excellent biosafety, superior to pEGFP-loaded unmodified CS particles. In vitro and in vivo gene transfection experiments based on HeLa cells confirmed that pEGFP loaded into CS-P particles exhibits much higher gene transfection efficiency than that loaded into unmodified CS. This work provides not only a new way to modify CS with quaternary phosphonium, but also a useful and feasible way to obtain new CS-based gene vectors with high gene transfection efficiency and biosafety for potentially practical clinic applications.

Gamma-ray radiation has always been a convenient and effective way to modify the interfacial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate (TMPTA) was incorporated into poly (ethylene terephthalate) (PET)/random terpolymer elastomer (ST2000) blends by melt-blending. The existence of TMPTA would induce the crosslinking of PET and ST2000 molecular chains at high temperatures of blending, resulting in the improvement in the impact strength but the loss in the tensile strength. When the PET/ST2000 blends were irradiated by gamma-ray radiation, the integrated mechanical properties could be enhanced significantly at a high absorbed dose. The irradiated sample at a dose of 100 kGy even couldn't be broken under the impact test load, and at the same time, has nearly no loss of tensile strength. Based on the analysis of the impactfractured surface morphologies of the blends, it can be concluded that gamma-ray radiation at high absorbed dose can further in situ enhance the interfacial adhesion by promoting the crosslinking reactions of TMPTA and polymer chains. As a result, the toughness and strength of PET/ST2000 blend could be dramatically improved. This work provides a facial and practical way to the fabrication of polymer blends with high toughness and strength.

The concept and the current theory on radiation emulsion polymerization are introduced. Some typical application examples, such as the synthesis of polyvinyl alcohol, polyacrylate and its composite latex, and polystyrene via γ-ray radiation-induced emulsion polymerization, have been presented to highlight the features of radiation emulsion polymerization technique. The production technique, mechanism, and basic recipes, as well as the product performance of two world's first and now popular industrial products by radiation emulsion technique, that is, low-temperature pigment printing binder and polyacrylate thickeners, are described in detail.

Radiation can induce cross-linking, degradation, oxidation, and reduction of different materials. Therefore, the radiation technology can be employed to prepare new functional materials. Nano material can be prepared via radiation reduction or polymerization. Functional materials prepared by radiation technology include: graphene and its nanocomposites used for electrode material, various noble metal nanomaterials, porous polymeric functional materials, and poly(ionic liquids) gel for removal of metal ions.

The structure design of SnO 2 -based anode material is crucial for the development of high-performance lithium-ion batteries (LIB). Here, a solvent-evaporation induced codeposition of monodispersed polystyrene (PS) microspheres (241 nm) and γ-radiation reduced graphene oxide (rGO) at the presence of the surfactant, cetyltrimethylammonium bromide (CTAB), has been firstly conducted to prepare a self-stand PS/rGO composite template film, which can transform into a porous SnO 2 /rGO composite material after being infiltrated with the precursor of SnO 2 and further calcinated at 420 °C. TGA, SEM, TEM, and nitrogen adsorption-desorption isotherms analyses indicate that the prepared SnO 2 /rGO composite material has 52.1 wt% of rGO, and a hierarchical pore structure, i.e., mesopores (3.312 nm) and macropores (∼200 nm) coexist. The half-cell using the hierarchical porous structured SnO 2 /rGO composite as the electrode exhibits an excellent cycle performance (850 mAh g −1 in 100 cycles at a current density of 0.3C) and rate property of 436 mAh g −1 at a current density of 4.5C. This work indicates that the incorporation of graphene-based materials into hierarchical porous SnO 2 matrix will be a potential way to obtain high-performance LIB anode material.

The surface modification of graphene oxide (GO) determines the interactions between GO and polymers, which possibly produces a significant impact on the mechanical properties of polymer. Here, GO was first modified with poly(glycidyl methacrylate) (PGMA) and triethylenetetramine (TTA) through γ-ray radiation. Then, a tiny small amount (0.04%) of the prepared modified GO was filled with a PET/ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (PET/ST2000) blend. The morphological analyses on these filled PET blends confirmed that the surface chemical structure of GO had a crucial impact on the mechanical property of the blend. The chemical bonding between GO and ST2000 was more efficient in improving the dispersibility of GO and the compatibility between PET and ST2000, leading to a 2.5-fold increase in the impact strength, along with a slight increase in tensile strength. However, the addition of reduced GO lacking polar groups caused fatal damage in the mechanical property of the blend.

Macroporous polystyrene microsphere/graphene oxide (PS/GO) composite monolith was first prepared using Pickering emulsion droplets as the soft template. The Pickering emulsion was stabilized by PS/GO composite particles in-situ formed in an acidic water phase. With the evaporation of water and the oil phase (octane), the Pickering emulsion droplets agglomerated and combined with each other, forming a three-dimensional macroporous PS/GO composite matrix with excellent mechanical strength. The size of the macrospores ranged from 4 μm to 20 μm. The macroporous PS/GO composite monolith exhibited high adsorption capacity for tetracycline (TC) in an aqueous solution at pH 4–6. The maximum adsorption capacity reached 197.9 mg g −1 at pH 6. The adsorption behaviour of TC fitted well with the Langmuir model and pseudo-second-order kinetic model. This work offers a simple and efficient approach to fabricate macroporous GO-based monolith with high strength and adsorption ability for organic pollutants.

Bi2WO6 has great potential applications in the field of photocatalyst due to its excellent visible-light photocatalytic performance. This work studied the detailed morphological evolution of Bi2WO6 particles synthesized in a simple hydrothermal system induced by the stabilizer poly(vinyl pyrrolidone) (PVP). The XRD and HRTEM results show PVP would not change the crystal structure of Bi2WO6, but the distribution of PVP on the initially formed Bi2WO6 nanosheets will induce the crystal growth, resulting in a distinct morphology evolution of Bi2WO6 with the increase of the concentration of PVP. At the same time, with the increase of the molecular weight of PVP, the morphology of Bi2WO6 varied from simple sheet-like (S-BWO) to some complicated morphology, such as flower-like (F-BWO), red blood cell-like (B-BWO), and square-pillar-like (SP-BWO). The photocatalytic performances of Bi2WO6 with various morphologies on the decomposition of RhB under visible light irradiation reveal that S-BWO has the best photocatalytic performance, while SP-BWO has the worst. This work not only gives the explanation of the inductive effect of PVP molecular chains on the morphological formation of Bi2WO6 particles, but also provides the controllable way to the preparation of Bi2WO6 with various morphologies taking advantage of the stabilizer PVP.

This work reports a simple and efficient preparation method of an inverse-opal-like macroporous polytetrafluoroethylene (IO-PTFE) film with a reusable matrix. At first, the pH-responsive poly(acrylic acid) (PAA) is grafted on the PTFE latex particles induced by γ-ray radiation. The stability of PAA grafted PTFE latex particles (PTFE-g-PAA) in water decreases in acid aqueous solution. As a result, PTFE-g-PAA particles can coprecipitate with monodispersed polystyrene (PS) microspheres from the acidic aqueous dispersion to form a composite particulate film. After the composite particulate film is etched with toluene to remove PS microspheres, a self-stand inverse-opal-like macroporous PTFE film can be successfully obtained. The macroporous PTFE film can be applied as the microreactor to synthesize uniform TiO2 particles. The separation of TiO2 microparticles and the recycle of PTFE-g-PAA particles can be simultaneously achieved simply in water by means of ultrasonification. The prepared TiO2 microparticles also show good photocatalytic performance. This work opens a new thought to prepare special macroporous polymeric materials, and expands the microsynthesis of inorganic or organic microparticles by taking advantage of polymeric macroporous materials.

The fabrication of raspberry-like poly(ethylene terephthalate)/polyacrylonitrile (PET/PAN) microspheres by γ -ray radiation-induced polymerization of acrylonitrile on micron-sized PET microspheres were first reported in this work. A PET emulsion was firstly prepared by dispersing a PET solution with 1,1,2,2-tetrachloroethane/phenol mixture as the solvent into an aqueous solution of sodium dodecyl sulfate. Then, PET microspheres were formed by precipitating the PET emulsion droplets from ethanol. The influence of the PET solvent and the weight ratio of ethanol to PET emulsion on the morphology of the PET microspheres had been investigated. After the surface of the prepared PET microspheres was grafted with poly(acrylic acid), the grafting polymerization of AN also had been successfully initiated by γ -ray radiation to form PAN microspheres with a size of about 100 nm on the PET microspheres. This work provides a new method to fabricate micron-sized PET microspheres, and further expands the functionalization of PET and its application fields.

A core-shell structured chitosan (CS)-based gene vector with a sustainable gene transfection effect was designed and successfully prepared in this study. The pEGFP was first combined with the thiolated and N-alkylated chitosan (TACS). Then, hydroxybutyl chitosan grafted with poly(ethylene glycol) (EG-HBC) was coated on the pEGFP-loaded TACS particles. The prepared pEGFP-loaded TACS@EG-HBC particles have a size of about 200 nm and little cytotoxicity. The in vitro and in vivo gene transfection experiments indicate that the pEGFP-loaded TACS@EG-HBC particles possess a better sustainable gene transfection capacity and a high transfection efficiency, which should be attributed to the biodegradation of the CS-based shell, the thiolation and N-alkylation modification on CS cores, and the grafted PEG chains with better biocompatibility. The in vivo gene expression of the loaded pEGFP can persist up to 60 days. This novel gene vector has a theoretical and practical significance for gene therapy with sustained transfection effect.

The synthesis of efficient and recyclable noble metal nanocatalysts has always been a hot research area in nanocatalysis. In this work, novel porous sulfonated polystyrene (SPS)/reduced graphene oxide (rGO) composite microspheres loaded with Au nanoparticles (AuNP@SPS/rGO) were synthesized through γ-ray radiation on a simple one-pot system, i.e. an aqueous solution containing cagelike porous SPS microspheres, GO, and HAuCl4. rGO and AuNPs with a size of about 12 nm were formed in water simultaneously under γ-ray radiation, and in situ loaded on cagelike porous SPS microspheres. The prepared cagelike AuNP@SPS/rGO microspheres showed far better catalytic performance than conventional non-supported AuNP catalysts, which completed the reduction of o-nitroaniline by NaBH4 within only 15 s. Furthermore, the prepared cagelike AuNP@SPS/rGO microspheres can be easily recycled from the reaction system by centrifugation with no loss of the catalytic activity. This work indicates that porous polymer/rGO composite microspheres can be used as a promising support to prepare recyclable metallic nanocatalysts with ultra-high catalytic activity.

An amine-containing benzoxazine (P-deta) based homopolymer and its epoxy (Ep) copolymers are investigated in this study. The structure of benzoxazine, prepared from phenol, diethylenetriamine and formalin, is confirmed by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The viscosity of P-deta is much lower than that of commercialized benzoxazine monomers. The curing profiles of P-deta with various Ep ratios are studied by deconvolution and the related mechanism is clarified. Epoxy will not increase the curing temperature of P-deta, instead, it helps P-deta overcome the conversion limitation and promotes the curing rate. The thermal and viscoelastic properties were determined and compared. The copolymer of P-deta/Ep = 50/50 (wt/wt) shows the highest glass transition temperature, higher than both individual homopolymers and other copolymers. Increasing benzoxazine fraction enhances modulus at room temperature but deteriorates the crosslink density. It can also enhances the char yield, but deteriorates the thermal stability of the copolymers.

The preparation of highly crosslinked polymer microspheres through the polymerization reaction in an alcohol–water solution without any stabilizer is still a difficult task. Here, we first reported a facile preparation of monodispersed highly-crosslinked microspheres through the polymerization of ethyleneglycol dimethacrylate (EGDMA) in an alcohol–water solution in the presence of a small amount of hydrophilic comonomer with a high reactivity ratio in a sealed autoclave at above the boiling point of the solvent, which can be considered as a solvothermal precipitation polymerization process. The formation mechanism of the poly(ethyleneglycol dimethacrylate) (PEGDMA)-based microspheres involving an initial nucleation process and the grow process of the microspheres was proposed and confirmed by the composition and distribution of the hydrophilic comonomer in the oligomers and microspheres, which were analyzed by 1 H and 13 C CP-MAS solid NMR spectra, elemental mapping, and XPS. This work opens a new economic and environmental-friendly way to prepare highly-crosslinked functional PEGDMA-based microspheres.

A sub-micron sized highly-crosslinked poly(ethyleneglycol dimethacrylate) (PEGDMA) microsphere supported nano-Au catalyst (PEGDMA@AuNP) was successfully prepared through a one-step synthesis method at room temperature and ambient pressure, taking advantage of the γ-ray radiation effect on a simple one-pot system, i.e. a methanol–water solution containing EGDMA, 4-VP, and HAuCl4. Electron microscopy, XPS, and XRD analyses proved that AuNPs of several nanometers had been synthesized and loaded simultaneously with the formation of crosslinked PEGDMA microspheres when the adsorbed dose rate and the initial concentration of HAuCl4 were controlled within a narrow range, i.e. 35–80 Gy min−1 and below 1 mmol L−1 of [HAuCl4]. The size of the prepared PEGDMA@AuNP microspheres changed little with the dose rate, but decreased with the initial [HAuCl4], from 900 nm at 0.1 mmol L−1 to 680 nm at 1 mmol L−1. At the same time, the size of AuNPs increases with the initial [HAuCl4], from 8 nm at 0.1 mmol L−1 to 35 nm at 1 mmol L−1. The prepared PEGDMA@AuNP microspheres can be dispersed stably in both water and organic solvent, CH3CN. They exhibit excellent catalytic efficiency not only on the reduction of Fe(CN)63− by NaBH4 in aqueous solution, but also on the cis–trans isomerization of azobenzenes in CH3CN at room temperature. A satisfactory repeatability of the catalytic performance of the prepared PEGDMA@AuNP microspheres was achieved in organic solvents. This work opens a new green simple and economic way to the synthesis of efficient and chemically-stable polymer-supported nano-metal catalysts.

The preparation of efficient and practical biomacromolecules imprinted polymer materials is still a challenging task because of the spatial hindrance caused by the large size of template and target molecules in the imprinting and recognition process. Herein, we provided a novel pathway to coat a NIR-light responsive lysozyme-imprinted polydopamine (PDA) layer on a fibrous SiO2 (F-SiO2) microsphere grown up from a magnetic Fe3O4 core nanoparticle. The magnetic core-shell structured lysozyme-imprinted Fe3O4@F-SiO2@PDA microspheres (MIP-lysozyme) can be easily separated by a magnet and have a high saturation adsorption capacity of lysozyme of 700 mg/g within 30 min because of the high surface area of 570 m(2)/g and the mesopore size of 12 nm of the Fe3O4@F-SiO2 support. The MIP-lysozyme microspheres also show an excellent selective adsorption of lysozyme (IF > 4). The binding thermodynamic parameters studied by ITC proves that the lysozyme should be restricted by the well-defined 3D structure of MIP-lysozyme microspheres. The MIP-lysozyme can extract lysozyme efficiently from real egg white. Owing to the efficient NIR light photothermal effect of PDA layer, the MIP-lysozyme microspheres show the controlled release property triggered by NIR laser. The released lysozyme molecules still maintain good bioactivity, which can efficiently decompose E. coli. Therefore, this work provides a novel strategy to build practical NIR-light-responsive MIPs for the extraction and application of biomacromolecules.

The synthesis and stable loading of metal nanoclusters have always been a hot and difficult topic in the field of nano-metal catalysts. In this work, micron-sized inverse opal SiO2 microspheres (IO-SiO2) are firstly prepared as the carrier of platinum nanoclusters (PtNCs) through a sol-gel process of tetraethyl orthosilicate (TEOS) on sacrificed polystyrene (PS) colloidal crystal microspheres template. After the IO-SiO2 carriers are dispersed into the aqueous solution of H2PtCl6 and irradiated by 60Co γ-ray radiation for a certain absorbed dose in a deoxygenized atmosphere, PtNCs with a size of less than 2 nm are in situ synthesized based on a redox equilibrium of Pt(0)/Pt(IV) induced by effect of the reductive species (eaq−, H ) and oxidizing radicals (HO ) produced by the radiolysis of water, and immobilized on IO-SiO2 without the help of any stabilizer. Due to the large pore volume of the IO-SiO2, the loading capacity of PtNCs can reach as high as 18.63 μg/mgmicrosphere. The prepared IO-SiO2-supported PtNCs (PtNCs@IO-SiO2) show excellent catalytic activity and recyclability for the reduction of o-nitroaniline by NaBH4 as the model reaction. This work offers a new route to prepare stable and high-performance metal nanocluster catalysts loaded on porous microspheres using γ-ray radiation technique.

Fibrous cyano-modified mesoporous SiO2 microspheres with specific surface area of ca. 300 m(2) g(-1) have been successfully fabricated respectively by in-situ synthesis and post-modification methods, based on the hydrolysis of ethyl silicate in the presence of (2-cyanoethyl)triethoxysilane at a certain condition. TEM observations show that the average diameters of the prepared fibrous cyano-modified SiO2 microspheres by these two methods are 68 and 211 nm, respectively. The N2 adsorption-desorption isotherms analysis on the fibrous SiO2 microspheres show sharp peaks in the 10-20 nm range. After the cyano groups transformed to amidoxime groups, the adsorption behavior of the fibrous amidoxime-functionalized mesoporous SiO2 microspheres for Fe(3+), Cu(2+), and Pb(2+) was investigated. The results show that the prepared SiO2 microspheres can selectively adsorb Pb(2+). The maximum equilibrium adsorption capacity for Pb(2+) could reach 284 mg/g. The desorption of Pb(2+) in 2M HNO3 completes within 60 min. The efficiency of the desorption is as high as 96.2%. This work provides the methods to prepare amidoxime-functionalized SiO2 microsphere with high specific surface area and total pore volume, which has the potential to be applied as an efficient adsorbent for specific heavy metal ions.

The preparation of supertoughening poly(ethylene terephthalate) (PET) blends has always been a practical and valuable task. In our work, PET resins grafted with poly(acrylic acid) (PAA), termed as PET-g-PAA, were first prepared through γ-ray radiation induced graft polymerization and blended in a partially miscible PET/ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (ST2000) system as the compatibilizer. The impact strength of the PET blends achieves the maximum at a 6 wt % of PET-g-PAA, but without the loss of tensile strength. Furthermore, much less of ST2000 is needed for the blends to possess high impact strength at the existence of PET-g-PAA. The SEM morphological analysis of the impact-fracture surface implies a good interfacial adhesion between ST2000 and PET matrix, which should be ascribed to the effective compatibilization by the in situ formed PET-g-PAA/ST2000 graft copolymer through the reaction between the —COOH groups and epoxy groups on ST2000.

The simultaneous γ-ray-radiation-induced grafting polymerization of acrylic acid on expanded polytetrafluoroethylene (ePTFE) film was investigated. It was found that the degree of grafting (DG) of poly(acrylic acid) (PAA) can be controlled by the monomer concentration, absorbed dose, and dose rate under an optimal inhibitor concentration of [Fe2+]=18 mmol/L. SEM observation showed that the macroporous structure in ePTFE films would be covered gradually with the increase of the DG of PAA. The prepared ePTFE-g-PAA film was immersed in a neutral silver nitrate solution to fabricate an ePTFE-g-PAA/Ag hybrid film after the addition of NaBH4 as a reduction agent of Ag+ to Ag atom. SEM, XRD, and XPS results proved that Ag nanoparticles with a size of several tens of nanometers to 100 nanometers were in situ immobilized on ePTFE film. The loading capacity of Ag nanoparticles could be tuned by the DG of PAA, and determined by thermal gravimetric analysis. The quantitative antibacterial activity of the obtained ePT...

The combination of NIR photothermal therapy and chemotherapy is considered as the promising technique for future cancer therapy. The key point of this technique is the design and synthesis of photothermal agents with high-efficiency photothermal effects and high chemical drug loading capacity. Herein, submicron-sized raspberry-like hollow-structured polypyrrole microspheres (H-PPy) were facilely prepared through in situ polymerization of pyrrole on monodispersed polystyrene (PS) template microspheres with a diameter of 220 nm, followed by the chemical etching of PS templates. The prepared H-PPy microspheres show rapid and remarkable photothermal effects in water under NIR laser irradiation (808 nm) only for 5 min. Further, a model small molecular drug, (S)-(+)-camptothecin (CPT), was loaded into the void core by a simple dispersion-permeation process through the micro-pores on the raspberry-like PPy shell, with a loading capacity of 0.14 mg/(mg H-PPy). The MTT assay and the in vitro NIR-laser triggered release behavior indicated that pure H-PPy microspheres have good biosafety, but the release of loaded CPT into H-PPy microspheres can be achieved with remarkable spatial/temporal resolution after NIR laser irradiation, which results in excellent synergistic effect of photothermal and chemical ablation on HeLa cells, as proved by fluorescence microscopy. This work provides convenient synthesis of a promising cancer therapy agent with high drug-loading capacity and efficient NIR light photothermal effects, which can perfectly achieve the synergistic NIR photothermal therapy and chemotherapy of PPy microspheres.

Poly(ethylene terephthalate)-g-polyacrylonitrile (PET-g-PAN) composite film with a porous surface was fabricated via gamma-ray-radiation-induced graft polymerization on PET film in an aqueous solution system. The original PET film was first irradiated by gamma ray in the aqueous solution of acrylic acid. Next, the graft polymerization of acrylonitrile (AN) was induced by gamma ray on the surface of the above modified PET film in an aqueous solution of AN. The prepared PET-g-PAN composite film has a smaller static water contact angle than the original PET film. The SEM and AFM images show that the grafted PAN layer on the surface of PET-g-PAN composite film is composed of closely-arranged spherical PAN microspheres with an average diameter of 30 nm. The gaps between the PAN microspheres form fine pores (less than 30 nm) on the surface. The gas barrier property of the PET-g-PAN composite film is much better than that of the original PET film. This work provides a facile and green method to prepare PET-g-PAN composite film with a controllable porous surface morphology by taking advantage of the radiation-induced graft polymerization technique in an aqueous solution system.