RSC Advances
·
2018
·Vol. 8
·期 56
·32193-32199
·
IF 2.936
Yiyuan Tang,Kai Chen,Jiacheng Li,Yuhong Feng,Gaobo Yu,Longzheng Wang,Xinyu Zhao,Yang Peng,Quan Zhang
In this study, a pH-responsive amphiphilic alginate (Ugi-Alg) was synthesized via Ugi reaction without using a catalyst. The structure of Ugi-Alg was confirmed by FT-IR and 1H NMR spectroscopy. Amphiphilic alginate can form micelles in an aqueous medium due to it's amphiphilic nature.. The impacts of Na+ concentration and pH on the micelle size were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The dynamic light scattering observations showed that micelle size increases with the decrease in Na+ concentration in aqueous solution. However, the micelle size decreases first and then increases as the pH value decreases from 5.3 to 2.0. Transmission electron microscopy confirmed that the mean size of micelles is 30–200 nm. In addition, a model hydrophobic pesticide (acetamiprid) was loaded in the micelles. The encapsulation efficiency and release behavior of micelles were studied, which could be controlled by Na+ concentration and pH. The results indicated that encapsulation efficiency of acetamiprid increases from 55% to 96% due to the increase in Na+ concentration from 0.01 M to 0.3 M. Moreover, with the decrease in pH from 5.3 to 2.0, encapsulation efficiency increases from 55% to 80%. Furthermore, the data of acetamiprid release kinetics could be well-fitted by the Weibull model.
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JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 22
·15430-15441
·
IF 2.993
Zhenfu Zhao,Liang Jing,Zhihai Wu,Jiong Cheng,Miaomiao Zhang,Yafei Hou
Halide perovskite quantum dots (PQDs) have been intensively studied because of their superior optical properties and have great potential applications in laser, display technology and light-emitting diodes (LEDs). Presently, high-efficiency green emissive CH 3 NH 3 PbBr 3 PQDs have been successfully fabricated. However, the synthesis of stable iodide-based CH 3 NH 3 PbX 3 (MAPbX 3 (X = Cl, Br, I), MA = CH 3 NH 3 ) QDs still faces significant challenges because they are sensitive to the moisture in open air. Herein, we investigated the effect of the solvent and ligand on the growth of the as-prepared MAPbBr 3 and MAPbI 3 sample, mainly involved in the volume ratio of N , N -dimethylformamide (DMF) and γ-butyrolactone (GBL) and the amount of n -octylamine in toluene. The results show that the low volume ratio of DMF and GBL is beneficial to prepare highly luminescent, stable and full-colored MAPbX 3 PQDs in open air. Besides, the PL emission peak of MaPbBr 3 PQDs can be adjusted from 430 to 513 nm via precisely controlling the amount of n -octylamine in toluene because of quantization. The obtained MAPbX 3 PQDs show high quantum yield and a wide range of tunable light emission from ultraviolet to near-infrared region. The MAPbX 3 PQDs, especially iodide-based MAPbX 3 PQDs, obtained from this method remain stable more than 3 months at ambient condition. We further demonstrated the multi-colored LEDs by using different color emissive MAPbX 3 PQDs as color converters and being subjected to excitation through a blue GaN chip. Furthermore, MAPbX 3 PQDs are expected to show interesting nanoscale optical properties and have great potential applications in electroluminescence devices, lasers and optical sensors.
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Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 41
·11104-11110
·
IF 5.976
Song Wei,Yue Liu,Mingyue Ma,Yao Wu,Lijian Huang,Daocheng Pan
To reduce the charge injection barrier, we attempt to synthesize thin-shell CdSe/ZnxCd1−xS core/shell quantum dots (QDs) in this work. A low-temperature (90–115 °C) synthetic scheme was developed for highly luminescent CdSe/ZnxCd1−xS core/shell QDs by employing short-chain tert-dodecanethiol as the ligand and low-boiling xylene or octane as the solvent. Thiol-capped CdSe/2ZnxCd1−xS core/shell QDs with two monolayers of the shells were directly synthesized in open air, including CdSe/2ZnS, CdSe/2Zn2/3Cd1/3S, CdSe/2Zn1/2Cd1/2S, CdSe/2Zn1/3Cd2/3S, CdSe/2CdS, and CdSe/1CdS/1ZnS core/shell QDs. These short-chain ligand capped and thin-shell QDs were used as the emitting layers to fabricate quantum dot light emitting diodes (QD-LEDs). The results showed that QDs coated with an alloyed Zn0.5Cd0.5S shell possess the optimal photoluminescence (PL) and electroluminescence (EL) properties as well as a maximum current efficiency of 12.5 cd A−1.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Yun Tang,Nan Yan,Zhiwei Wang,Hudie Yuan,Yalou Xin,Hongfeng Yin
Ligand-assisted reprecipitation (LARP) technique is a powerful approach for the synthesis of organometal halide perovskite nanocrystals (PNCs). The morphology and surface property of the formed PNCs which determine their optical properties are ultrasensitive to the synthetic parameters. To guarantee the batch-to-batch reproducibility of PNCs with excellent optical properties, it is of central importance to better understand the factors influencing the formation of PNCs during LARP process. Herein the dual-factor of the amount of perovskite precursor and the polarity of mixture solvent was modified by varying precursor solution volume (PSV) in the LARP system. The concentration, size, surface state and optical properties of the synthesized CH 3 NH 3 PbBr 3 PNCs as a function of PSV were systematically investigated aiming to understand the influence of the dual-factor on the nucleation and growth of PNCs. Experimental results revealed that few crystal nuclei was generated due to lower amount of precursor at lower PSV, which was favorable for the growth of large perovskite crystals. At the higher PSV, the inhibition of crystal growth with increased amount of precursor was compensated by increasing the polarity of mixture solvent, which led to the dissolution of surface ligands and eventually growth of large perovskite crystals. The obtained results on PSV-dependent synthesis of PNCs will be used as a guide to optimize the synthetic parameters in the LARP process.
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ACS Sustainable Chemistry & Engineering
·
2018
·
IF 6.14
Qingyu Wang,Chen Wang,Shang Ma,Ping Lu,Jian Dong
Kinetic hydrate inhibitors (KHIs) are polymers that play a vital role in gas energy production, transport, and storage. A series of polyaspartamides based on l-aspartic acid were designed to serve as potential KHIs. Tuning the fine structures of the polyaspartamides can inhibit the tetrahydrofuran hydrate formation more effectively than classical KHIs, i.e., poly(N-vinylcaprolactam) (PVCap) and poly(N-vinylpyrrolidone) (PVP). When the hydrophobic side chain is longer, the polyaspartamide is more effective. For elucidation of the polymer structure–property relationships in the inhibition of the clathrate hydrate, the molecular-level interactions between the polyaspartamides and tetrahydrofuran hydrate were studied. Dynamics of water surrounding the polymers probed by NMR relaxometry demonstrate that the polyaspartamides can bind tightly with water molecules in the hydrate, resulting in faster transverse relaxation times of the nonfreezable water. This phenomenon can be interpreted by quantum chemical simulations and nonfreezable bound water analysis by calorimetry. The simulations show that the interaction between the polyaspartamides and the clathrate hydrate is featured by the formation of strong hydrogen-bonding, rendering severe distortion and destruction of the clathrate cages. High levels of nonfreezable bound water per polymer repeat unit were found in the amphiphilic polymers. Polyaspartamide could be used as a green resource for prevention of gas hydrate formation in energy production.
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MATERIALS RESEARCH BULLETIN
·
2017
·
IF 2.446
Hua Liu,Zumin Wang,Haiyan Li,Hao Wang,Ranbo Yu
Industrial wastewater containing both organic and inorganic pollutants is being generated all the time. Efficient materials are highly needed to purify the polluted water. Thus, a hierarchical structured α-Fe 2 O 3 with excellent adsorptive property has been synthesized by using a facile hydrothermal method. It can be prepared in macroscopic quantity. The as-synthesized α-Fe 2 O 3 with silkworm cocoon-like morphology shows high efficiency in adsorbing Congo red (CR), Methyl orange (MO) and Cr(VI). The removal efficiency of CR, MO and Cr(VI) can reach 99.2%, 83.9% and 100% under appropriate conditions. Besides, this α-Fe 2 O 3 shows high adsorptive ability for mixed CR and Cr(VI) in aqueous solution and the final removal rates can reach 94.7% and 97.9%, respectively. The adsorption kinetics fits well with the pseudo-second-order kinetic model. The results indicate that the product may find potential application in purification of wastewater containing both organic and inorganic pollutants.
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Nanoscale
·
2017
·Vol. 10
·期 3
·1532-1539
·
IF 7.367
Xiaolong Wu,Liling Ma,Shan Sun,Kai Jiang,Ling Zhang,Yuhui Wang,Haibo Zeng,Hengwei Lin
In this work, a versatile platform for the highly efficient preparation of graphene quantum dots (GQDs) with diverse properties was developed. First of all, an excess amount of oxidants and an additional high temperature step of the Hummers’ method for the synthesis of graphene oxide (GO) was applied to obtain nanosized graphene oxide (NGO). Then, high quality GQDs (quantum yields up to 18.2%) with different photoluminescence emission wavelengths, adjustable hydrophilicity–hydrophobicity, and selective cell organelle imaging capacity can be facilely achieved through a one-pot hydrothermal reaction between the NGO and ammonia, fatty primary amines, or amino-substituted organelle targetable compounds, respectively. The superior features of the as-developed method are extremely high conversion ratio (ca. 60 wt% from graphite to the functional GQDs) and great expandability. Such a high conversion ratio is deemed to be due to effectively decreasing aggregation of the NGO (in comparison with GO) during the post-treatment process. This work provides a robust strategy for the highly efficient preparation of GQDs with diverse properties and functions, and is believed to be beneficial for boosting their applications in the future.
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RSC Advances
·
2017
·Vol. 7
·期 77
·49074-49082
·
IF 3.108
Yizhou Huang,Yazhou Tian,Yuanyuan Li,Xiaocun Tan,Qing Li,Jue Cheng,Junying Zhang
A series of epoxy systems with tunable rigid-flexibility were prepared by the curing reaction of bisphenol F diglycidyl (DGEBF), a single-ended amine with alkyl chains (n-butyl, octyl, dodecyl), 4,4′-diaminodiphenylmethane (DDM) and 4,4′-diaminodicyclohexylmethane (H-DDM). By means of adjusting the composition of the curing agent (the molar ratio between H-DDM and DDM), nano- and submicron-sized phase separations were observed by atomic force microscopy (AFM). And diffraction peaks were not observed in the wide angle X-ray scattering (WAXS) characterization which revealed that there was no crystallization in the modified epoxy resin. Besides, the result of nanoIR characterization proved that the aggregation of aliphatic chains led to the microphase separation structure, which can remarkably improve the mechanical properties of epoxy resins. The effects of side chains on the mechanical and thermal properties of epoxy networks were investigated. Especially, the EC8-5′ (the molar ratio between H-DDM and DDM was 45/55, the mass ratio of the n-octyl amine to DGEBF was 5 : 100) sample exhibited splendid mechanical properties with an attractive tensile strength of 88.4 MPa, an elongation at break of 6.6% and a tensile modulus of 3.5 GPa.
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CHEMISTRY OF MATERIALS
·
2024
·
IF 7.2
Huan Tian,Yi Liu,Feng-Lei Jiang
Perovskite nanocrystals attract growing interest owing to their unique optoelectronic properties. However, their chemical stability is relatively poor due to their ionic nature. In this work, we found that inorganic cations (e.g., Cs+) and ligands (e.g., didodecyldimethylammonium bromide, DDAB), used in the synthesis of CsPbBr3 nanocrystals (NCs) at ambient temperature, quickly converted CsPbBr3 NCs to Cs4PbBr6 NCs during the synthesis or postsynthetic treatment. These cations (Cs+, DDA+) were involved in both the chemical composition and dissociation of CsPbBr3 NCs. Nevertheless, DDA+ induced the generation of an impurity in addition to Cs4PbBr6 NCs due to its different nature from that of Cs+. The transformation process was observed by optical spectroscopy and transmission electron microscopy. The reverse transformation of Cs4PbBr6 NCs to CsPbBr3 NCs can be carried out completely by adding sufficient PbBr2 into Cs4PbBr6 NCs. Therefore, the forward and backward reactions were driven by Cs+ and Pb2+. With additional DDAB for passivation during the reverse transformation, the resulting product possessed a better photoluminescence quantum yield (PLQY, ∼90%) compared with that without the involvement of DDAB (∼69%). By considering the Cs4PbBr6 NCs as the Cs source, the reverse transformation can be analogized to the synthesis of CsPbBr3 NCs, providing a possible strategy for synthesizing luminescent perovskite NCs at room temperature with theoretical stoichiometry.
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POLYMER BULLETIN
·
2015
·Vol. 72
·期 12
·3097-3117
·
IF 1.438
Chen Xiuqiong,Yan Huiqiong,Sun Wei,Feng Yuhong,Li Jiacheng,Lin Qiang,Shi Zaifeng,Wang Xianghui
As a kind of novel hydrophobic drug carrier materials, the drug-loaded nanofibers were successfully fabricated using amphiphilic alginate derivative (AAD) and poly (vinyl alcohol) (PVA) by electrospinning method. The AAD was synthesized by amide linkage attachment of octylamine onto the carboxylic group of alginate, which was characterized by the means of elemental analysis, FT-IR spectrometer, 1 H NMR spectrometer and fluorescence measurement. Experimental results showed the amidation of alginate was successful, in which the degree of modification was 0.27 and the critical aggregation concentration in 0.15 mol/L aqueous NaCl solution was 0.43 mg/mL. The octyl groups of AAD could effectively make alginate chains flexible and enhance chain entanglements through the hydrophobic interactions between octyl groups. In contrast to sodium alginate
(SA)/PVA blend solutions, AAD/PVA blend solutions showed more excellent electrospinnability. Additionally, the different volume ratios of SA or AAD to PVA played an important role in the formation and morphology of the electrospun blend nanofibers. Although the amidation of alginate could not fundamentally alter the spinnability of alginate, the content of alginate in the blend nanofibers was appropriately increased. The new generated drug-loaded AAD/PVA (20/80) blend nanofibers exhibited relatively continuous and uniform nanofibers with the average diameter of 191.72 nm. Compared to the drug-loaded SA/PVA (20/80) blend nanofibers, the drug-loaded AAD/PVA (20/80) blend nanofibers presented a sustained release performance with the slow release of about 76 % λ-cyhalothrin during the initial period of 10 h.
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RSC Advances
·
2015
·Vol. 5
·期 86
·70238-70243
·
IF 3.84
Yu Chen,Jinhui Wang,Jing Li,Xinxin Li,Shuo Wei
The II–VI group/monoamine hybrid was a novel inorganic/organic (I/O) layered structure and it exhibited a strong quantum confinement effect and well-defined Mn2+-doped luminescence, which was imperative and valuable academically for its application. In this work, the pure and well-crystalline (ZnS:Mn)2·oa (oa = octylamine) hybrid was prepared by solvothermal synthesis and its thin films were fabricated by the drop-casting method. The 5 at% Mn2+-doped hybrid exhibited a strong Mn2+ luminescence at 597 nm with a 300 nm excitation. The inner filter effect (IFE) for this luminescence was investigated and verified by detecting three selected environmental contaminant species: n-butyl xanthate (BX), crystal violet (CV), and reaction black 5 (RB5), which indicated that this hybrid thin film had a good luminescence IFE-based linear response for the μM species solution. Furthermore, the 597 nm luminescence remained intact for the solution with a pH from 4 to 10 and the hydrophobicity of the hybrid thin film was favorable for its rapid and multiple IFE-based detection. Therefore, this hybrid thin film is a competitive candidate for the new-generational fluorescence sensors to probe the occurrence of these environmental contaminants.
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MOLECULAR PHARMACEUTICS
·
2016
·
IF 4.342
Meirong Huo,Yao Liu,Lei Wang,Tingjie Yin,Chen Qin,Yanyu Xiao,Lifang Yin,Jiyong Liu,Jianping Zhou
A redox-sensitive micellar system constructed from an O,N-hydroxyethyl chitosan–octylamine (HECS-ss-OA) conjugate with disulfide linkages between the hydrophobic alkyl chains and hydrophilic chitosan backbone was synthesized for triggered intracellular delivery of hydrophobic paclitaxel (PTX). In aqueous environments, conjugates formed micelles with high PTX loading (>30%). Mechanistically, the sensitivity of HECS-ss-OA micelles to reducing environments was investigated using the parameters of in vitro release and particle size. Intracellular release of nile red fluorescence alongside cytotoxicity studies further confirmed the potency of redox-sensitive micelles for intracellular drug delivery compared with redox-insensitive micelles. Additionally, an in vivo study confirmed the efficacy of PTX-loaded micelles in tumor-bearing mice with superior antitumor efficacy and diminished systemic toxicity when compared with the redox-insensitive micelles and a PTX solution. These results demonstrate the potential of redox-sensitive HECS-ss-OA micelles for intracellular trafficking of lipophilic anticancer drugs.
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