含多芳香环嵌段聚合物PS-b-PAH对碳纳米管的修饰

以芘丁酸为原料通过酯化反应制备了含芘丁单元的苯乙烯基单体,再利用原子转移自由基聚合法（ATRP）合成了分子量可控的嵌段聚合物PS-b-PAH,采用凝胶渗透色谱（GPC）、核磁共振（1H-NMR）等测试手段对产物进行了表征。采用聚合物对碳纳米管表面修饰,比较了聚苯乙烯PS和嵌段聚合物PS-b-PAH修饰碳纳米管后在THF...     

PMMA-b-PBMA-b-PNVIm(Bu)BF_4离子液体嵌段聚合物的RAFT合成及表征

以S-十二烷基-S′-(α,α′-二甲基-α″-乙酸)-三硫代碳酸酯为链转移剂,制备了窄分布的聚甲基丙烯酸甲酯(PMMA)大分子链转移剂,用大分子链转移剂来引发第二单体甲基丙烯酸丁酯(BMA)制备了PMMA-b-PBMA二嵌段聚合物。再以二嵌段聚合物为大分子链转移剂引发N-乙烯基咪唑(NVIm)合成PMMA-b-PBMA-b-PNVIm三嵌段聚合物。通过与溴代正丁烷发生季铵化反应并与氟硼酸钠进行阴离子交换得到离子液体嵌段聚合物PMMA-b-PNVIm(Bu)BF_4。运用核磁、红外和凝胶渗透色谱及差示扫描量热等技术对产物的结构、分子量及分子量分布和玻璃化转变温度进行表征。结果表明,嵌段聚合物为PMMA166-b-PBMA145-b-PNVIm144,分子量分布为1.68,合成过程具有活性/可控聚合特征。     

两亲性嵌段共聚物PS-b-P4VP·BuBr的合成及自组装

采用可逆加成断裂链转移聚合(RAFT)制备了苯乙烯和4-乙烯基吡啶嵌段共聚物(PS-b-P4VP),并用溴代正丁烷对其进行季铵化,得到两亲性嵌段共聚物PS-b-P4VP.BuBr。采用核磁共振(1H-NMR)、红外光谱(FT-IR)、凝胶渗透色谱(GPC)和有机元素分析对聚合物结构进行表征分析。将PS-b-P4VP.BuBr在水溶液中进行自组装研究,透射电镜(TEM)结果显示,共溶剂N,N-二甲基甲酰胺(DMF)和四氢呋喃(THF)的比例可以调控聚集体的形态,随着THF含量增加,聚集体形态从球形依次向棒状、大复合胶束转变。     

一种带有醚键结构的阴离子交换树脂的合成

研究了以大孔型氯甲基化交联聚苯乙烯母球为原料,与烷基氨基醇钠反应,合成带有醚键结构的叔胺树脂,进一步季铵化为强碱性阴离子交换树脂。系统研究了叔胺化工艺条件,并对季铵树脂进行了热稳定性评价。结果表明,与常规的强碱性阴离子交换树脂相比,其热稳定性已有明显提高,使用温度可以提高20℃左右,拓展了强碱性阴离子交换树脂的应用领域。     

含大侧基嵌段共聚物的合成及胶束的聚焦超声响应行为

以聚乙二醇单甲醚(mPEG)为亲水段,聚己内酯(PCL)为疏水段,并在mPEG与PCL之间引入体积庞大的侧基——氨基酸端基功能化基团Cys(trt),制备了含大侧基的mPEG-Cys(trt)-Cys(trt)-PCL-Cys(trt)-Cys(trt)-mPEG三嵌段聚合物。采用核磁共振氢谱对产物结构进行了表征。通过选择性溶剂诱导方法制备了嵌段聚合物胶束,通过动态光散射表征了高强度聚焦超声作用前后嵌段聚合物胶束的尺寸大小。使用芘作为荧光探针,研究了大侧基嵌段共聚物胶束的高强度聚焦超声响应行为。结果表明,这种含大侧基的三嵌段聚合物能在水溶液中形成粒径约50nm的胶束,并且超声作用后其粒径增大至85nm左右。超声作用使芘在胶束中增溶,荧光强度随超声功率增加和时间延长而增加。     

阳离子两亲性三嵌段共聚物的合成及自组装

采用可逆加成-断裂链转移(RAFT)自由基聚合及季铵化后处理方法制备出2种苯乙烯(St)和对氯甲基苯乙烯(VBC)的阳离子两亲性三嵌段共聚物PS-b-Q-PVBC-b-PS和Q-PVBC-b-PS-b-Q-PVBC。PS和PS-b-PVBC-b-PS的相对分子质量分别为8100和11700;PVBC和Q-PVBC-b-PS-b-Q-PVBC的相对分子质量分别为3600和12700,可以发现,二者的相对分子质量和嵌段比例均相近。以二甲基甲酰胺(DMF)为共溶剂,分别以去离子水和甲苯为选择性溶剂,对2种聚合物的自组装行为进行对比研究,探索了分子结构对聚合物自组装行为的影响。结果表明,当在相同的条件下进行自组装时,若成壳嵌段在大分子两端,聚合物自组装产生球形胶束聚集体;若成壳嵌段在大分子中间,聚合物自组装形态则是核壳胶束聚集体(选择性溶剂含量较低时)或棒状、球状胶束的聚集体(选择性溶剂含量较高时)。     

部分氟化嵌段型阴离子交换膜的制备

以接枝α,α′-二溴对二甲苯的氟化芳香族链段作为大分子引发剂,在链的末端引发烯烃聚合,合成了三嵌段聚合物.然后在脂肪族链段接枝季铵型侧链进行功能化,制备出部分氟化的嵌段型阴离子交换膜.表征结果显示,由于嵌段间的亲疏水性差异,膜内形成明显的微相分离.其中,膜FPAE-PVBC-QA-20 (IEC=1.51 mmol/g)在80℃下离子电导率达到87.8 mS/cm;浸泡于80℃、2 mol/L NaOH溶液中500 h后仍保留74.5%的离子电导率,具有良好的耐碱性;单电池功率密度达到131.7 mW/cm~2.     

21臂星形两亲性嵌段共聚物β-CD-g-21（PS-b-PAA）的合成与表征

通过连续原子转移自由基聚合(ATRP)技术,首次合成出3个系列以β-环糊精(β-CD)为核心、内嵌段为刚性链聚苯乙烯(PS)、外嵌段为聚丙烯酸(PAA)的21臂两亲性星形嵌段共聚物β-CD-g-21(PS-b-PAA)。并利用核磁氢谱、红外光谱、凝胶色谱对所得聚合物的化学结构、相对分子质量及其分布进行了表征。证实β-CD的21个羟基均发生了聚合反应,所得的共聚物相对分子质量分布窄,均在1.35以下。通过水解嵌段聚合物大分子链和β-CD之间的酯键,计算出PSb-PAA的相对分子质量分别为3100、4200、5800。实验结果表明,合成出的星形嵌段聚合物结构明确,相对分子质量分布可控。     

PBMA-b-PDMS-b-PBMA嵌段聚合物的合成与表征

以羟基封端的聚二甲基硅氧烷和α-溴代异丁酰溴为原料,制备了双官能度Br-PDMS-Br,并以此为大分子引发剂,CuCl和2,2’-联吡啶为催化剂,通过原子转移自由基聚合制备了聚甲基丙烯酸丁酯-聚二甲基硅氧烷-聚甲基丙烯酸丁酯(PBMA-b-PDMS-b-PBMA)三嵌段聚合物。利用傅里叶变换红外光谱仪(FT-IR)、核磁(1 H NMR)、凝胶渗透色谱分析仪(GPC)、热失重分析仪(TGA)、接触角测试仪、扫描电子显微镜(SEM)对三嵌段聚合物的结构及聚合反应进行了表征与测试。结果表明三嵌段聚合物具有较好的热稳定性、疏水性和微相分离。     

具有吗啉侧基的聚氨基酸嵌段共聚物的控制释放研究

通过大分子引发开环聚合和侧基改性,制备了一种侧链含有吗啉丙基的聚乙二醇-聚(吗啉丙基-天冬酰胺)-聚丙氨酸三嵌段共聚物。利用肿瘤细胞外、细胞内和正常组织pH值环境的差异,调节聚合物载药纳米粒子的结构和性能实现肿瘤部位靶向释放的目的。在水溶液中,此聚合物可自组装形成一种核-壳-冠型的3层共聚物胶束,其中疏水性的聚丙氨酸链段自聚集形成胶束的核,聚(吗啉丙基-天冬酰胺)链段形成具有pH值-响应性的壳层,用于包埋和释放药物,外围的聚乙二醇链段可以提供一个稳定的水合冠层,延长药物的体内循环时间。以阿霉素作为模型药物在自组装的过程中包埋到胶束内。研究发现,由于吗啉环在酸性条件下的质子化导致链段亲疏水性质发生明显变化,载药胶束的药物释放能力随环境pH值的降低药物的释放速率显著增加。     

Light and dark-activated biocidal activity of conjugated polyelectrolytes

This Spotlight on Applications provides an overview of a research program that has focused on the development and mechanistic study of cationic conjugated polyelectrolytes (CPEs) that function as light- and dark-active biocidal agents. Investigation has centered on poly-(phenylene ethynylene) (PPE) type conjugated polymers that are functionalized with cationic quaternary ammonium solubilizing groups. These polymers are found to interact strongly with Gram-positive and Gram-negative bacteria, and upon illumination with near-UV and visible light act to rapidly kill the bacteria. Mechanistic studies suggest that the cationic PPE-type polymers efficiently sensitize singlet oxygen ((1)O(2)), and this cytotoxic agent is responsible for initiating the sequence of events that lead to light-activated bacterial killing. Specific CPEs also exhibit dark-active antimicrobial activity, and this is believed to arise due to interactions between the cationic/lipophilic polymers and the negatively charged outer membrane characteristic of Gram-negative bacteria. Specific results are shown where a cationic CPE with a degree of polymerization of 49 exhibits pronounced light-activated killing of E. coli when present in the cell suspension at a concentration of 1 μg mL(-1).     

Rational design of phosphonate/quaternary amine block polymer as an high-efficiency antibacterial coating for metallic substrates

Developing advanced technologies to address the bacterial associated infections is an urgent requirement for metallic implants and devices.Here,we report a novel phosphonate/quaternary amine block polymer as the high-efficiency antibacterial coating for metallic substrates.Three pDEMMP-b-pTMAEMA block polymers that bearing identical phosphonate segments(repeat units of 15)but varied cationic segments(repeat units of 8,45,and 70)were precisely prepared.Stable cationic polymer coatings were constructed on TC4 substrates based on the strong covalent binding between phosphonate group and metallic substrate.Robust relationship between the segment chain length of the polymer coating and the antibacterial property endowed to the substrates have been established based on quantitative and qualitative evaluations.Results showed that the antibacterial rate of the modified TC4 surface were 95.8%of S.aureus and 92.9%of E.coli cells attached.Interestingly,unlike the cationic free polymer or cationic hydrogels,the surface anchored cationic polymers do compromise the viability of the attached C2C12 cells but without significant cytotoxicity.In addition,the phosphonate/quate rnary amine block polymers can be easily constructed on titanium,stainless steel,and Ni/Cr alloy with significantly improved antibacterial property,indicating the generality of the block polymer for surface antibacterial modification of bio-metals.     

两性聚苯硫醚的制备和性能

通过对磺化聚苯硫醚（P-SO₃）的溴化、季铵基和叔铵基的取代反应,制备了两性聚苯硫醚（P-SO₃-TMA和P-SO₃-DMA）.测试了两性聚苯硫醚的溶解性、比浓黏度、特性粘数和热稳定性等性能,研究了几种关键因素对这些性能的影响。结果表明:通过溴化和取代反应,在磺化聚苯硫醚分子链上引入极性基团（季铵基和叔铵基）增强了分子链极性,使两性聚苯硫醚能溶解在极性较大的溶剂中,使P-SO₃-TMA和P-SO₃-DMA的比浓黏度随着水溶液pH值的增加大致呈上升趋势;水溶液的稀释使分子链上磺酸基与季铵基或叔铵基之间的相互吸引力减弱,构象变得疏松,从而使比浓黏度增大;受阳离子影响的大小排序为:NH<₄⁺Li+++,Mg²⁺2+,受阴离子影响的大小排序为Br---;在纯水中,两性聚苯硫醚表现出一种比磺化聚苯硫醚稳定的剪切速率.在饱和食盐水中,两性聚苯硫醚的黏度随着剪切速率的增大迅速降低。耐温性较磺化聚苯硫醚也得到提高。     

Chloride/sulfate ion exchange kinetics at high solution concentration

Kinetics of chloride-sulfate exchange and reverse exchange and sulfate self-exchange at high salinity on three acrylate-base anion exchange resins with quaternary ammonium, tertiary amine, and secondary amine groups, respectively, have been examined. In all cases, evidence points to rate control by intra-particle diffusion. At low conversion, rates are slightly lower than predicted on the basis of the Nernst-Planck equations; this is attributed to initial retardation by film diffusion. For forward and reverse exchange (sulfate and chloride, respectively, taken up by the resin), but not for isotopic sulfate exchange, rates at high conversion tend to be somewhat higher than predicted; this is tentatively attributed to changes in water content of the resins in the course of conversion.     

侧链多阳离子型氟化聚芴醚阴离子交换膜及其全钒液流电池性能

阳离子基团的分布对阴离子交换膜的微观相态和阴离子传导率有显著的影响.为开发全钒液流电池用高性能阴离子交换膜,本文通过向含有二甲胺基团的氟化聚芴醚前驱体接枝含阳离子烷基链的方式,合成了具有相似离子交换容量的一系列侧链多阳离子型氟化聚芴醚.实验结果表明,多阳离子侧链的引入能促进微观相分离的形成并提升阴离子传导率.同时,侧链...     

Temperature-swing adsorption of proteins in water using N-isopropylacrylamide copolymer gel particles

The adsorption and desorption behaviors of bovine serum albumin (BSA) in water for temperature-responsive polymer gel particles have been investigated by the temperature-swing operation between 298 and 313 K, where the cationic N-isopropylacrylamide (NIPA) gels copolymerized with vinylbenzyl trimethylammonium chloride (VBTA) or 2-(dimethylamino)ethyl methacrylate (DMAEMA) were used. The NIPA-VBTA and the NIPA-DMAEMA copolymer gels adsorbed BSA while the NIPA homopolymer gel hardly adsorbed BSA, indicating that the copolymer gels adsorb BSA through the electrostatic attraction between the positively charged groups in the gels and the negatively charged BSA. The adsorption amounts for the NIPA-DMAEMA gels were smaller than those for the NIPA-VBTA gels. This may be because almost every VBTA group, which is a quaternary ammonium salt, can be positively charged in water, while only some of the tertiary amine DMAEMA groups are protonated in water. Moreover, it was found that both the copolymer gels with a large mesh size of the polymer network repeatedly adsorbed BSA at 298 K and desorbed some of pre-adsorbed BSA at 313 K by the temperature-swing operation. This BSA desorption may result from the decrease of the number of the positively charged groups accessible to BSA due to the shrinking of the constituent polymer chains.     

Experimental and theoretical investigation into the correlation between mass and ion mobility for choline and other ammonium cations in N2

A number of tertiary amine and quaternary ammonium cations spanning a mass range of 60-146 amu (trimethylamine, tetramethylammonium, trimethylethylammonium, N,N-dimethylaminoethanol, choline, N,N-dimethylglycine, betaine, acetylcholine, (3-carboxypropyl)trimethylammonium) were investigated using electrospray ionization ion mobility spectrometry. Measured ion mobilities demonstrate a high correlation between mass and mobility in N(2). In addition, identical mobilities within experimental uncertainties are observed for structurally dissimilar ions with similar ion masses. For example, dimethylethylammonium (88 amu) cations and protonated N,N-dimethylaminoethanol cations (90 amu) show identical mobilities (1.93 cm(2) V(-1) s(-1)) though N,N-dimethylaminoethanol contains a hydroxyl functional group while dimethylethylammonium only contains alkyl groups. Computational analysis was performed using the modified trajectory (TJ) method with nonspherical N(2) molecules as the drift gas. The sensitivity of the ammonium cation collision cross sections to the details of the ion-neutral interactions was investigated and compared to other classes of organic molecules (carboxylic acids and abiotic amino acids). The specific charge distribution of the molecular ions in the investigated mass range has an insignificant affect on the collision cross section.     

两亲水溶性阳离子聚电解质研究1.聚(苯乙烯-丙烯酰胺甲基二羟乙基苄基氯化铵)丙烯酰胺)的合成和表征

以ＡＩＢＮ为引发剂,苯乙烯与丙烯酰胺在１,４－二氧六环溶剂中共聚,得到Ｐ（Ｓｔ－Ａｍ）,通过Ｍａｎｎｉｃｈ反应,甲醛与二乙胺反应生成Ｎ,Ｎ－二羟乙基甲醇胺,然后与Ｐ（Ｓｔ－Ａｍ）缩合,最后以苄氯为季铵化试剂,与上述反应产物进行季铵化反应,得到阳离子聚。     

Hydrophobic but hygroscopic polymer films--identifying interfacial species and understanding water ingress behavior

The hydrophobic but hygroscopic nature of polydimethylsiloxane (PDMS) with quaternary ammonium cationic side chains adsorbed on a SiO(2) surface was investigated with sum frequency generation vibration spectroscopy (SFG) and attenuated total reflectance infrared spectroscopy (ATR-IR). PDMS with cationic side chains, named cationic polymer lubricant (CPL), forms a self-healing boundary lubrication film on SiO(2). It is interesting that CPL films are externally hydrophobic but internally hydrophilic. The comparison of SFG and ATR-IR data revealed that the methyl groups of the PDMS backbone are exposed at the film/air interface and the cationic side groups and counterions are embedded within the film. The hydrophobicity must originate from the surface CH(3) groups, while the ionic groups inside the film must be responsible for water uptake. The surface hydrophobicity can alleviate the capillary adhesion while the hygroscopic property enhances the mobility and self-healing capability of the CPL boundary lubrication film.     

环氧季铵盐对明胶的阳离子化改性

碱性条件下,环氧季铵盐1,2-环氧丙基二甲基十二烷基氯化铵(EPQA)与明胶侧链的伯胺基、羟基反应,得到阳离子改性明胶EPQA-GE,核磁共振(~(13)C-NMR、~1H-NMR)及元素分析结果表明,精氨酸、赖氨酸的氨基以及羟脯氨酸的羟基参与了反应,季铵阳离子基团成功引入了明胶结构中。X射线衍射及差示扫描量热分析结果表明,明胶的微观相结构受阳离子含量的影响较大,引入的季铵离子越多,EPQA-GE的近程有序度越高。以水和乙二醇为标准液,测定了阳离子化程度不同的EPQA-GE膜的接触角,并应用Owens-Wendt方程计算了表面自由能,结果显示阳离子基团的引入增加了明胶的亲水性,且随着阳离子化程度增加,膜表面的亲水性增强。抗菌实验结果表明阳离子的引入增加了明胶的抗菌性,EPQA-GE对革兰氏阳性菌的抗菌效果优于对革兰氏阴性菌的抗菌性。