Self-assembly of Gradient Copolymer Synthesized by Spontaneous Batch RAFT Emulsion Polymerization and Its Application on Encapsulating Ag Nanoparticles

The gradient copolymers of acrylic acid and trifluoroethyl methacrylate(coded as P(TFEMAgrad-AA)) were synthesized via reversible addition-fragmentation transfer(RAFT) emulsifier-free emulsion polymerization. The spontaneous batch feeding approach was used to control the gradient chain sequence. Transmission electron microscopy(TEM) analysis revealed that the P(TFEMA-grad-AA) can self-assemble to form spherical micelles, rodlike micelles or vesicles in selective solvents. Morphological transition of the P(TFEMA-grad-AA) micelles was sensitive to the water content of the dioxane/water mixed solvent. More interestingly, Ag nanoparticles(NPs) were encapsulated by the P(TFEMA-grad-AA) micelles during the selfassembly process. The gradient chain sequence made the Ag NPs easily enter the core of the micelles, even when P(TFEMA-grad-AA) had less hydrophobic fluoro-units and more hydrophilic units. TEM images with energy dispersive spectrometer indicated that the nanocomposite micelles consisted of a Ag NPs core and a gradient copolymer shell.     

The effect of umbrella-type branching on the blood circulation and tumor targeting of star-branched PLA-PMPC copolymer micelles

The effect of branching on the blood circulation and tumor targeting of polymer nanovehicles in vivo was investigated in this study. For the purpose, star-branched poly(lactic acid) and poly(2-methacryloyloxyethyl phosphorylcholine)(PLA-PMPC)copolymers with umbrella-type AB_3,(AB_3)_2, and(AB_3)_3 architecture were synthesized by branching at the PLA core. Micelles self-assembled from these copolymers were used to evaluate the effect of core branching on blood circulation and tumor targeting. The results showed that branching changed the behavior of polymeric self-assembly in solution, thereby changing the size and surface anti-fouling performance of the polymeric micelles. Moreover, star-branched copolymer micelles with a higher branching degree allowed their payload to persist better in blood(half-time prolonged from 7.1, 8.6 to 13.8 h) and for a 1.72-fold higher content at the tumor site. These studies suggest that raising the branching degree of amphiphilic copolymer potentially offers a promising strategy for the design of carriers capable of enhanced circulation and targeting in vivo.     

聚合物反胶团萃取氨基酸的研究

利用德国BASF公司生产的Pluronic型和PluronicR型两类嵌段聚合物制备聚合反应胶团萃取氨基酸（L－苯丙氨酸和L－异亮氨酸）， 聚合物反胶团对氨基酸的萃取平衡特性，实验表明，聚合物反胶团对氨基酸的萃取平衡时间与纯有机溶剂的物理萃取相比差别很小，溶质在反胶团外壳部分与其内部水池间的平衡分配系数K都普遍较大，另外，当氨基酸水溶液的PH值接近等电点时，反胶团萃取达到最佳效果。通过理论分析得到如下推断，聚合物反胶团对两亲性氨基酸的增溶主要在基外壳部分，很可能是包裹在聚氧丙烯外壳内或缠绕在聚氧丙烯链之间，亲油作用和氢键作用是聚合物反胶团萃取的主要推动力。     

包覆Fe_2O_3超微粒复合共聚物的动态力学性能研究

采用种子乳液聚合法将Ｆｅ２Ｏ３超微粒包覆在苯乙烯／丙烯酸／丙烯酸丁酯（Ｓｔ／ＡＡ／ＢＡ）核－壳型复合共聚物中，形成包覆有无机粒子的有机高分子核－壳型复合微球，从微观的分子尺寸上改变了复合共聚物的性能，并着重研究Ｆｅ２Ｏ３的含量对这种复合共聚物的动态力学性能的影响。结果表明，随着Ｆｅ２Ｏ３含量的增加，复合共聚物的内耗明显增加，刚性显著下降。因而Ｆｅ２Ｏ３加入对复合共聚物有增韧作用，改善了复合共聚物的力学性能。     

Antifogging and antibacterial properties of amphiphilic coatings based on zwitterionic copolymers

Tackling fogging and microbial infection problems related to the endoscope lens remain challenges due to visual disturbances and bacterial threats to human health. Herein, highly transparent antifogging and antibacterial coatings were developed in a facile way by thermal curing of zwitterionic copolymers poly(n-butyl methacrylate-co-2-aminoethyl methacrylate-co-sulfobetaine methacrylate)s with 1,3,5-triformylbenzene. Characterizations of surface chemical composition and wettability suggested that the copolymer coatings exhibited amphiphilicity with a hydrophobic surface and internal hydrophilicity. The prepared amphiphilic coating exhibited excellent antifogging properties both in vivo and in vitro. The introduction of hydrophobic n-butyl methacrylate and cationic aminoethylmethacrylate could improve the stability and antibacterial capability of the coating. The growth inhibition rates of the coatings against Staphylococcus aureus and Escherichia coli were up to 99% and the copolymer coatings with the zwitterionic groups had low hemolytic rates less than 3%. The amphiphilic copolymer coatings combined antifogging and antibacterial properties may have a promising potential for applications in biomedical devices.     

碘介导金包银核壳纳米粒子的合成及SERS应用

金包银核壳纳米粒子有望在保持纳米银优良表面增强拉曼（SERS）增强性能的同时,提高银纳米粒子的抗氧化能力;但是目前制备完整纳米金壳包裹的纳米银粒子仍较困难. 以AuI₄^-代替传统使用的AuCl₄^-,利用碘与金、银原子的相互作用,避免了金与纳米银核的电化学置换反应而导致的结构缺陷,制备得到了完整均匀包裹的金包银核壳粒子（Ag@Au NPs）. 该粒子不仅具有与银类似的SERS增强效果,同时具有可以与纳米金相比拟的抗氧化性能. 将上述方法得到的金包银核壳粒子成功地应用于玫瑰红B、亮蓝等合成色素以及农药百草枯的测定.     

温度响应性玻璃球基复合载体的制备及表征

报道了一种新型的智能响应性玻璃球基复合载体的制备方法.首先通过自由基聚合法将双键类单体N-异丙基丙烯酰胺、甲基丙烯酸羟丙酯和甲基丙烯酸(3-三甲氧基硅)丙酯合成随机嵌段共聚物;然后借助自制的底喷式流化床反应器将共聚物溶液均匀喷涂于玻璃球基表面,并利用高温退火作用实现共聚物与玻璃球基之间的键合,从而形成共聚物/玻璃球基复...     

Deposition of Ag nanoparticles on carbon microspheres surface: Evaluation of structures,electrochemical and optical properties

A hybrid material of carbon microspheres (CMSs) with Ag decoration (Ag/CMSs) was developed. Poly (3-hexylthiophene):Ag/CMSs composite film was prepared by spin-coating. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, thermogravimetric analysis and cyclic voltammetry were employed to analyze the morphologies, structures, thermal properties and energy levels of Ag/CMSs. The optical property of the composite films was characterized by ultraviolet-visible spectrophotometry and fluorescent spectrometry. The results indicate that silver nanoparticles (Ag NPs, d = 10-20 nm) are distributed on the surface of CMSs. LUMO and HOMO energy levels of Ag/CMSs are -3.97 and -5.52 eV, below the vacuum energy level, respectively, indicating that it is feasible to use Ag/CMSs as an electron acceptor. Ag NPs are blended into the active layer to trigger localized surface plasmon resonance, and consequently enhance light harvesting. The coupling of surface plasmons and excitons increased the probability of exciton dissociation.     

刚柔嵌段共聚物在选择性溶剂中的自组装

嵌段共聚物在选择性溶剂中能够自组装形成"核-壳"结构的胶束,由于胶束的尺寸处于纳米量级,因此利用嵌段共聚物的自组装制备纳米材料已成为当今高分子科学和材料科学的重要研究课题.刚柔嵌段共聚物是指分子链中同时含有刚性嵌段和柔性嵌段的共聚物,它在溶液中通过不同嵌段对溶剂的选择性可以自组装成球形、棒状、囊泡等多种多样的纳米聚集体.本文简单介绍了嵌段共聚物和分子自组装的概念,总结了刚柔嵌段共聚物在刚棒选择性溶剂、柔性链选择性溶剂和非选择性溶剂中自组装的最新研究进展,并对刚柔嵌段共聚物在溶液中自组装的前景进行了展望.     

还原响应性两亲性梳型聚合物的合成及表征

以端氨基功能化的聚乙二醇单甲醚为引发剂,引发γ-炔丙基-L-谷氨酸-N-羧基内酸酐（PLG-NCA）开环聚合反应,获得聚氨基酸聚乙二醇两亲性嵌段共聚物。并以此为基础,用click方法合成带有二硫键标记的还原敏感性的可降解两亲性梳型嵌段聚合物。最后所得的这种聚合物在水溶液中自主装形成可降解的两亲性的敏感性胶束。这种带有敏感性的胶束可以用于抗癌药物的包覆以及运输和适时的释放;这种胶束具有更高的稳定性和更高的药物释放性。实验采用盐酸阿霉素作为包裹药物,在1/15mol pH=7.4的PBS溶液中进行自主装包裹药物。     

油包水“多面液胞”中水滑石的接枝共聚合

为克服通常丙烯酰胺(AM)类油包水乳液的不稳定性及减少油相,研究了在油包水"多面液胞"(W/OPHC)中进行的AM类水溶性单体的自由基接枝聚合反应.首次引入水滑石(LDH3)作为接枝骨架,合成一系列W/OPHC型阳离子、阴阳离子型的有机-无机两性LDH3接枝共聚产物.重点报道该新型聚合反应过程,从动力学角度研究其最佳反应条件;用透射电镜(TEM)表征PHC在W/O乳液中的百分率和PHC的体积大小;用红外表征最终产物的结构.这类产物是目前最新开发的高效多功能水处理剂,可用于絮凝剂和污泥脱水剂等.     

磁性MnFe2O4/Ag复合纳米粒子的 制备与抑菌性能测试

采用水热法合成了磁性空心MnFe2O4纳米粒子,然后用3-氨丙基三乙氧基硅烷对其表面进行了改性并吸附银离子,还原后成功制备了磁性MnFe2O4/Ag复合纳米粒子,并采用X射线衍射仪、透射电镜、磁强计、紫外光谱等对试样进行了表征.通过抑菌圈法对MnFe2O4/Ag复合纳米粒子的抑菌性能进行了测试.结果表明:磁性空心MnFe2O4纳米粒子没有抑菌性能;MnFe2O4/Ag对大肠杆菌的抑菌圈半径为1.78 cm,对金黄色葡萄球菌的抑菌圈半径为2.14 cm;MnFe2O4/Ag的抑菌持久性检测结果说明,所制备的载银磁性复合纳米粒子抑菌剂的稳定性较好,抑菌性能较持久.     

具有“门控”效应的智能型纳米药物载体

肿瘤作为目前困扰人们的一种常见疾病,其治疗手段和抗肿瘤药物的研发倍受关注.针对化疗方法中至关重要的药物载体,综述了基于两亲性聚合物及其与无机纳米粒子组装的复合物的纳米药物载体实现控制释放的机理、种类以及在生物医药方面的意义等,并为今后智能型药物载体的设计提出了一点展望.     

Completely green synthesis of Ag nanoparticles stabilized by soy protein isolate under UV irradiation

A completely green pathway for the preparation of Ag nanoparticles was proposed, by using soy protein isolate (SPI) as stabilizer under UV irradiation and H2O as the environmentally benign solvent throughout the preparation. Transmission electronic microscopy (TEM) and zeta potential characterization results indicated that the Ag nanoparticles were stable and well dispersed with an average diameter about 13 nm, and X-ray diffraction (XRD) analysis of SPI/Ag composite nanoparticles confirmed the formation of metallic silver. UV-Vis spectrum showed that the Ag nanoparticles dispersion solution had the maximum absorbance at about 430 nm due to surface plasmon resonance of the Ag nanoparticles. Infrared spectroscopy confirmed that the polypeptide backbone of SPI was not cleaved during the conjugation process and that some active amino groups were oxidized. The SPI/Ag composite nanoparticles have excellent antibacterial activity against two representative bacteria, staphylococcus aureus (Gram positive) and escherichia coli (Gram negative) in the presence of SPI.     

Gap-plasmon of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>@Ag core-shell nanostructures for highly enhanced fluorescence detection of Rhodamine B

A novel gap-plasmon of Fe₃O₄@Ag core-shell nanoparticles for surface enhanced fluorescence detection of Rhodamine B (RB) was developed. Fe₃O₄@Ag core-shell nanostructures with Ag shell and Fe₃O₄ core were synthetized by self-assembled method with the assistance of 3-mercaptopropyl trimethoxy silane (MPTS). To study the RB fluorescence enhanced by gap-plasmon, the fluorescence properties of RB on the substrates with different nanogap densities were systematically investigated, and the results showed that the fluorescence intensity of RB on Fe₃O₄@Ag core-shell NPs substrate was much stronger than that on bare glass substrate, and the fluorescence intensity was further improved by using multilayer Fe₃O₄@Ag core-shell NPs substrate which had higher nanogap density. Different from the mechanism that is based on the maximum overlap of the surface plasmon resonance (SPR) band and emission band, the mechanism of the fluorescence enhancement in our work is based on the localized surface plasmon (LSP) and the gap plasmon near-field coupling with the Fe₃O₄@Ag core-shell NPs. Besides, the detection limit obtained was as low as 1×10^-7 mol/L, and the Fe₃O₄@Ag core-shell NPs substrate had high selectivity for RB fluorophores. It was demonstrated that the Fe₃O₄@Ag core-shell NPs substrate had activity, good stability, and selectivity for fluorescence detection of RB. And the detection of RB by the surface plasmon enhanced fluorescence was more convenient and rapid than the traditional detection methods in previous works.     

RAFT法制备pH敏感两亲性嵌段聚合物

利用酰胺化反应,合成pH敏感性．单体甲基丙烯酸二异丙胺基乙酯（DPA）和亲水性单体N-（2－羟丙基）甲基丙烯酰胺（HPMA）,并通过可逆加成-断裂链转移聚合（RAFT）制备pH敏感两亲性二嵌段聚合物。结果显示：该聚合物在水溶液和生理盐水中具有较好的pH敏感性能,并能在一定pH范围内的溶液中形成稳定的胶束,有望作为治疗肿瘤的药物载体。     

Synthesis of nano-CaCO_3 composite particles and their application

Nano-calcium carbonate composite particles were synthesized by the soapless emulsion polymerization technique of dou-ble monomers. The composite particles formation mechanism was investigated. The effects of composite particles on the mechanical properties of nano-CaCO3-ABS (acrylonitrile-butadiene-styrene copolymer) composite material were studied. It was validated that the composite particles are made up of the nano-calcium carbonate cores and the shells of alternating copolymers of butyl acrylate (BA) and styrene (St). The shells are chemically grafted and physically wrapped on the surface of nano-calcium carbonate particles.When the composite particles were filled in ABS matrix, the CaCO3 particles are homogeneously dispersed in the composite material as nanoscales. The impact strength of the composite material is obviously enhanced after idling appropriate amounts of composite particles. It can be concluded that the soapless emulsion polymerization of double monomers is an effective method for nano-CaCO3 surface treatment.     

聚四乙烯基吡啶复合型CdTe量子点合成

以巯基丙酸为稳定剂,采用水热法合成了CdTe量子点,并以CdTe量子点为核,包覆4-乙烯基吡啶(4-VPy),制备得到核壳型4-VPy /CdTe荧光纳米复合粒子.用荧光(FL)分光光度、透射电子显微镜(TEM)等分析测试手段,对得到的荧光纳米复合粒子的性能进行表征.结果表明,4-VPy /CdTe纳米复合粒子是核壳粒子拥有较好的水溶性,有效地提高了量子点的稳定性.吸收光谱和荧光光谱表明,所合成的CdTe量子点具有优异的发光特性.     

ARGET ATRP制备甲基丙烯酸短全氟酯共聚物及其性能

为了研究新型环保型单体甲基丙烯酸（N-甲基全氟己烷磺酰胺基）乙酯（C6SMA）的共聚规律和产物性能,用电子转移再生催化剂原子转移自由基聚合（ARGET ATRP）法制备C6SMA和甲基丙烯酸甲酯（MMA）的无规共聚物,测试共聚动力学,利用凝胶渗透色谱（GPC）、核磁共振（1H-NMR）和接触角法表征共聚物的结构等特性.结果表明,ARGET ATRP很好地调控C6SMA/MMA的共聚反应,实现共聚物分子量及其分布(PDI)的控制,共聚物组成未发生明显的漂移现象,均聚物及共聚物膜的静态接触角数据表明,可以通过共聚有效降低氟单体用量同时兼具良好的疏水疏油性能,共聚物中C6SMA的摩尔分数在19%即可超过聚四氟乙烯（PTFE）的疏水疏油性.