两亲性三嵌段共聚物PLA-PEG-PLA的合成及其自组装行为的研究

采用阴离子开环聚合方法合成了两亲性嵌段共聚物PLA-PEG-PLA。用1H-NMR和GPC对聚合物的结构进行了表征,通过透射电子显微镜(TEM)观察了聚合物在离子液体中自组装的形貌,发现PLA-PEG-PLA在离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM][PF6])中形成了胶束。当疏水链长固定时,胶束的自组装形状主要依赖于亲水链的长度。     

两亲性嵌段共聚物的合成及其在离子液体中的自组装行为

采用阴离子开环聚合法合成了嵌段共聚物PCL—PEG—PCL（聚己内醋-聚乙二醇-聚己内酯）。用1HNMR和GPC等对产物的分子量和组成进行表征,将其在离子液体中配成胶束,通过透射电镜（TEM）观察胶束的微观结构。研究结果表明,当疏水链段长度固定时,胶束的自组装形状主要依赖于亲水链的长度。     

铕(Ⅲ)诱导聚苯乙烯-聚4-乙烯基吡啶嵌段共聚物的自组装行为及表征

研究了含共轭结构氮杂环的非离子嵌段共聚物参与形成的稀土配合物纳米胶束的形态结构及荧光性能。通过可逆加成-断裂链转移(RAFT)自由基聚合合成了聚苯乙烯-聚4-乙烯基吡啶(PS-b-P4VP)两亲性嵌段共聚物,并以邻菲罗啉(Phen)作为小分子配体协同反应,与Eu(Ⅲ)离子配位诱导自组装成具有核壳结构的荧光聚合物聚集体纳米胶束,分别采用紫外-可见吸收光谱、透射电镜、荧光光谱对胶束的结构形态及其荧光性能进行表征。结果表明,PS-b-P4VP和Phen都通过分子上的氮原子与Eu(Ⅲ)形成螯合键,在N,N-二甲基甲酰胺溶液中共同参与配位络合形成了聚集体;PS-b-P4VP和Phen都对Eu(Ⅲ)离子的荧光强度起到了明显的增强作用;成功制备出尺寸可控的球形纳米胶束,通过调节纳米胶束的大小,使其应用于太阳能电池及其它光电光伏领域。     

两亲性嵌段聚合物-铕杂化纳米球的结构与荧光性能

主要研究了稀土铕离子配合物中两亲性嵌段共聚物和小分子配体对铕离子荧光性能的影响。通过可控/"活性"自由基聚合方法中的可逆加成-断裂转移(RAFT)法合成一系列具有不同链段长度的两亲性嵌段共聚物:聚甲基丙烯酸甲酯-b-聚丙烯酸(PMMA-b-PAA)。在适当的溶剂N,N-二甲基甲酰胺(DMF)中,以稀土铕离子作为诱导中心,邻菲罗啉(phen)作为小分子配体协同反应,诱导聚甲基丙烯酸甲酯-b-聚丙烯酸(PMMA-b-PAA)进行自组装。成功制备了尺寸可控并具有优良荧光性能的球形纳米胶束,调整球形胶束的尺寸可以应用于有机物太阳能电池等光伏领域。     

两亲性聚乙烯醇-b-聚苯乙烯嵌段共聚物的合成及表征

采用原子转移自由基聚合(ATRP)法合成了具有两亲性的聚乙烯醇-b-聚苯乙烯嵌段共聚物P(VA-b-St)。首先利用调聚反应制备了带三氯甲基端基的聚醋酸乙烯大分子引发剂。以联二吡啶作配体、氯化亚铜为催化剂,引发苯乙烯单体聚合,得到结构明确的P(VAc-b-St)嵌段共聚物,而后通过皂化反应将其水解,从而得到两亲性嵌段共聚物P(VA-b- St);产物采用FT-IR、1H NMR、GPC等方法进行结构表征。P(VA-b-St)在不同浓度溶剂中的自组装行为用TEM进行了观察,结果表明:P(VA-b-St)可在DMF溶剂中形成球状囊泡结构,其尺寸达到纳米级。     

两亲性嵌段共聚物胶束的制备及对药物的控制释放

两亲性嵌段共聚物在水溶液中通过自组装可以形成以疏水嵌段为核,以亲水嵌段为壳的胶束。其亲水嵌段对胶束起稳定和保护作用,在胶束中通过物理、化学方式载入药物,可以实现对药物的控制释放。简述了嵌段共聚物胶束化的一些基本途径,如利用氢键,离子间相互作用,改变温度,自由基共聚,改变外部环境pH等,探讨了其对模型药物的控制释放。     

pH和磁场响应型嵌段共聚物基纳米复合材料的制备

采用自制链转移剂,通过可逆加成-断裂链转移聚合法制备p H和磁场响应型嵌段共聚物基纳米复合材料Y-054B。利用透射电子显微镜、扫描电子显微镜、傅里叶变换红外光谱仪等对其进行了表征。结果表明:Y-054B中的嵌段共聚物由疏水性且对p H敏感的甲基丙烯酸甲酯与丙烯酸共聚物嵌段和亲水性N-乙烯基吡咯烷酮均聚物嵌段组成;Y-054B在水溶液中可自组装生成纳米胶束,胶束平均粒径约70 nm,其中的自组装铁磁性成分平均粒径约8 nm,分散均匀,稳定性良好。     

两亲嵌段共聚物的合成及其自组装研究进展

作者介绍了两亲嵌段共聚物的活性阴离子聚合、基团转移聚合、开环歧化聚合、活性阳离子聚合、活性／可控自由基聚合、缩聚法、嵌段共聚物化学改性法等合成方法,并对其自组装形成聚合物纳米胶束的制备方法、形成机理以及在药物控制释放领域的应用进行了综述,并对其未来发展趋势进行了展望。     

两亲性苯乙烯嵌段共聚物的合成及结构表征

以α,α'-二甲基-α-乙酸-三硫代碳酸酯(BDATC)为链转移剂,采用可逆-加成-断裂链转移(RAFT)自由基聚合方法合成了末端带有—COOH官能团的两亲性嵌段共聚物聚苯乙烯-b-聚甲基丙烯酸聚乙二醇单甲醚-b-聚苯乙烯(PSt-b-POEOMA-b-PSt),这种含有亲水性端基的嵌段共聚物可以自组装成核-壳结构的纳米微粒,用于载药高分子的模板研究。利用FTIR、1HNMR、GPC对产物结构进行表征,用热失重(TG)和差示扫描量热(DSC)的方法研究了3种不同比例的嵌段共聚物的热性能。实验结果表明,通过RAFT聚合方法得到了所设计的嵌段共聚物,相对分子质量(简称分子量,下同)分布1.35左右;嵌段共聚物的热稳定性较好,通过玻璃化转变温度(Tg)的变化推测出嵌段共聚物中两种嵌段比例对两嵌段相容性的影响。     

铕(Ⅲ)诱导嵌段聚合物配位自组装及性能表征

利用制备的RAFT试剂合成了两亲性嵌段聚合物PS-b-PAA,以其为高分子配体,并以邻菲罗啉(Phen)为第二配体与铕(Ⅲ)离子配位诱导自组装,在N,N-二甲基甲酰胺溶液(DMF)中得到了聚合物纳米胶束,该纳米胶束能够形成核壳结构,通过透射电镜、荧光光谱对该稀土配合物纳米胶束的形态结构及荧光性能进行了表征。该形貌尺寸可控的纳米胶束具有优良的荧光性能,在太阳能电池等发光材料中有着广泛的应用。     

系列非离子两亲嵌段共聚物PEO-b-PBA的制备及性能研究

两亲嵌段聚合物通常用在现代水性涂料配方中充当分散剂、消泡剂和流变控制剂等关键助剂,而且也是水性树脂乳液聚合技术的重要乳化剂品种,可以规避小分子乳化剂易于在界面富集而导致涂膜耐水性较差的缺点。通过大分子引发剂的原子转移自由基聚合(ATRP)来制备一系列聚氧乙烯与聚丙烯酸丁酯嵌段的非离子型两亲共聚物PEO-b-PBA。采用Wilhelmy吊片法、动态光散射和透射电镜(TEM)等手段详细研究了此类两亲聚合物水溶液的表面张力和聚集体粒径以及微观形貌,并就其与非离子表面活性剂TX-100的起泡与乳化性能进行了对比分析。     

Synthesis of amphiphilic temperature‐sensitive poly(N‐isopropylacrylamide)‐block‐poly(tetramethylene carbonate) block copolymers and micellar characterization

Amphiphilic thermally sensitive poly(N‐isopropylacrylamide)‐block‐poly(tetramethylene carbonate) block copolymers were synthesized by ring‐opening polymerization of tetramethylene carbonate with hydroxyl‐terminated poly(N‐isopropylacrylamide) (PNiPAAm) as macro‐initiator in the presence of stannous octoate as catalyst. The synthesis involved PNiPAAm bearing a single terminal hydroxyl group prepared by telomerization using 2‐hydroxyethanethiol as a chain‐transfer agent. The copolymers were characterized using ¹H NMR and Fourier transform infrared spectroscopy and gel permeation chromatography. Their solutions show reversible changes in optical properties: transparent below the lower critical solution temperature (LCST) and opaque above the LCST. The LCST depends on the polymer composition and the media. Owing to their amphiphilic characteristics, the block copolymers form micelles in the aqueous phase with critical micelle concentrations (CMCs) in the range 1.11–22.9 mg L^?1. Increasing the hydrophobic segment length or decreasing the hydrophilic segment length in the amphiphilic diblock copolymers produces lower CMCs. A core‐shell structure of the micelles is evident from ¹H NMR analyses of the micelles in D₂O. Transmission electron microscopic analyses of micelle morphology show a spherical structure of both blank and drug‐loaded micelles. The blank and drug‐loaded micelles have an average size of less than 130 nm. Observations show high drug‐entrapment efficiency and drug‐loading content for the drug‐loaded micelles. Copyright © 2010 Society of Chemical Industry     

Synthesis, isothermal crystallization and micellization of mPEG-PCL diblock copolymers catalyzed by yttrium complex

Amphiphilic biodegradable mPEG-PCL diblock copolymers have been synthesized using rare earth catalyst: yttrium tris(2,6-di-tert-butyl-4-methylphenolate) [Y(DBMP)₃] in the presence of monomethoxy poly(ethylene glycol) (mPEG, M_n = 5000) as macro-initiator. The diblock architecture of the copolymers was thoroughly characterized by ¹H NMR, ¹³C NMR and SEC. The molecular weights of mPEG-PCLs can be well controlled by adjusting the feeding molar ratio of ?-CL to mPEG. Thermal and crystallization behaviors of the diblock copolymers were investigated by DSC and POM (polarized optical microscope). The crystallization property of mPEG-PCL block copolymers depends on the length of PCL blocks. As the molecular weight of PCL block increased, the crystallization ability of mPEG block was visibly restrained. Aqueous micelles were prepared by dialysis method. The critical micelle concentration of the copolymers, which was determined to be 0.9-6.9 mg/L by fluorescence technique, increased with the decreasing of PCL block length. The particle sizes determined by DLS were 30-80 nm increasing with the PCL block length. TEM images showed that these micelles were regularly spherical in shape.     

生物可降解两亲性嵌段共聚物胶束的制备及其对叶酸的控制释放

以甲氧基聚乙二醇(mPEG)为引发剂,在辛酸亚锡催化下引发ε-环己内酯(CL)开环聚合,合成了聚乙二醇-聚己内酯两亲性嵌段共聚物(mPEG-PCL)。通过FTIR、1H-NMR及GPC等表征手段确定了mPEG-PCL的组成及结构。采用芘荧光探针法、透射电镜和动态激光光散射研究了聚合物在水中的自组装行为。结果表明:聚合物在水溶液中能够自组装形成粒径小于100 nm的规则球状胶束,且具有较低的临界胶束浓度(7.35×10-3 g/L);模型药物(叶酸)成功负载于聚合物纳米胶束内,并且能延缓叶酸的释放,其释药速率受载药量和释放介质pH的影响。     

pH响应型mPEG-PCL嵌段共聚物胶束用作药物运输

该文合成了一种具有pH敏感性,较低毒性的两亲性嵌段共聚物以用于药物运输。聚乙二醇-聚己内酯(mPEG-PCL)是以聚乙二醇单甲醚为引发剂,开环己内酯聚合而成,阿霉素则是通过顺乌头酸裂解键连在聚己内酯的末端。该嵌段聚合物通过核磁共振、红外光谱等进行表征。共轭阿霉素后的嵌段聚合物在水溶液中能够自组装形成胶束,胶束粒径约为45.4 nm,透射电镜显示胶束具有近似的球形结构。阿霉素在pH=4.0下的释放速率明显快于pH=7.4下的释放速率。mPEG-PCL在细胞培养中无细胞毒性,包载阿霉素的胶束在人类MCF-7乳腺癌细胞上表现出迟缓的细胞毒性。通过共聚焦显微镜观察游离阿霉素和mPEG-PCL-DOX胶束在MCF-7细胞内的定位说明载体能够携带阿霉素进入细胞。     

双亲性聚合物胶束研究进展

两亲性嵌段聚合物在选择性溶剂中可以自组装成为一系列的形态结构,如球状胶束、柱状胶束、层状胶束、囊泡和微管结构,尤其自组装形成胶束,这一结构可做为药物输送材料已成为高分子科学和生物医学研究领域的热点之一。文章对上述领域进行综述,结合作者研究的课题,分成三大类进行阐述：胶束的制备方法;影响胶束的因素;胶束的表征方法。     

两亲性无规共聚物的自组装及模拟释药性能

通过自由基聚合得到两亲性甲基丙烯酸-co-甲基丙烯酸甲酯无规聚合物P(MAA-co-MMA)。用红外光谱、核磁共振和黏度法对聚合物进行表征。用此共聚物进行自组装成胶束,并用罗丹明B进行模拟载药、释药。用激光粒度散射仪和紫外分光光度计对胶束载药、释药性能进行表征。结果表明,此聚合物能够自组装形成315～384 nm胶束。胶束的药物包封率达1%,在模拟生理pH值条件下载药胶束能起到明显的长循环药物缓释作用。     

Synthesis and morphology transformation of amphiphilic diblock polyurethane copolymers in aqueous solution

Amphiphilic block copolymers possess both hydrophobic and hydrophilic properties and can form versatile micellar structures in aqueous solution. The aim of the research presented was to prepare a series of non‐ionic amphiphilic diblock polyurethane copolymers (PUn) based on isophorone diisocyanate, monoallyl‐end‐capped poly(ethylene oxide) and poly(propylene oxide) (PPO), followed by an investigation of their micellization properties and morphology transformation in aqueous solution. The PUn samples were synthesized by condensation polymerization. These polyurethanes exhibit surface tension as low as 33.7–37.0 mN m^?1. There is an obvious decrease in critical micelle concentration as the hydrophobic PPO molecular weight increases. According to transmission electron microscopy, the morphology of aggregates of the copolymers can be tuned by varying the concentration in aqueous solution rather than organic solvent. For example, for PU7, large compound micelles are produced instead of vesicles. For PU17, the concentration can be used to control the size and thickness of vesicles. Vesicle size increases from 60 to 500 nm and vesicle thickness from 40 to 60 nm with concentration ranging from 0.003 to 0.03 wt%. The study shows that the copolymers in aqueous solution have excellent surface activities. In addition, they can self‐assemble into large compound micelles or vesicles at certain concentrations. Moreover, the synthesis method described allows one to obtain a desired morphology of aggregates by adjusting the composition of hydrophilic and hydrophobic segments, which provides a novel and simple way to obtain particles on the nanometer scale. Copyright © 2010 Society of Chemical Industry     

光/温度双重响应性两亲嵌段共聚物PEO-b-P(NIPAM-co-NBA)的制备及其光控释药性能研究

通过可逆加成-断裂链转移聚合(RAFT)的方法合成具有光敏和温敏性的两亲嵌段共聚物PEO-b-P(NIPAM-co-NBA),使用核磁氢谱手段表征两亲嵌段共聚物具有紫外光响应性,同时以尼罗红为药物模型分子考查光敏含量对胶束释放性能的影响,证实了光敏单元含量少的聚合物胶束溶液中尼罗红的释放速率最快。