Double open mouse-like terpyridine parts based amphiphilic ionic molecules displaying strengthened chemical adsorption for anticorrosion of copper in sulfuric acid solution

In this study,the benign target double terpyridine parts based amphiphilic ionic molecules(AIMs 1,2)and the reference single terpyridine segment included AIMs(AIMs 3,4)were synthesized through a multi-step method,and the molecular structures were fully characterized.The excellent anticorrosion of the target AIMs for copper surface in H_(2)SO_(4) solution was demonstrated by the electrochemistry analysis,which was more superior over those of the reference AIMs.The standard adsorption free energy changes of the target AIMs calculated by the adsorption isotherms were lower than -40 kJ·mol^(-1),suggesting an intensified chemical adsorption on metal surface.The molecular modeling and molecular dynamic computation of the studied AIMs were performed,demonstrating that the target AIMs exhibited lower highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps and greater adsorption energies than the reference ones.The chemical adsorption of the AIMs on metal surface was revealed by various spectroscopic methods including scanning electron microscopy,atomic force microscopy,Fourier transform infrared spectroscopy,attenuated total reflection infrared spectroscopy,Raman and X-ray diffraction.

聚醚型两亲分子对水泥净浆收缩的影响及机理

将5种聚醚型两亲分子作为减缩组分,测试了其对水泥净浆收缩变形的影响,探究了表面张力与胶束粒径分布对收缩的影响机理.结果表明:二乙二醇丁醚、三丙二醇甲醚和聚乙二醇400不形成稳定的胶束,减缩效果随着孔溶液表面张力的降低而提高;聚醚改性硅油具有低临界胶束浓度(CMC),形成的胶束大小为30 nm左右,影响了聚醚改性硅油单体在毛细孔溶液表面的铺展,同时细化了水泥石的孔结构,减缩效果较差;含氟聚醚具有超低的表面张力及CMC,其胶束易产生聚沉,孔溶液的有效含量极低,无减缩效果.

非离子及两性型碳氢表面活性剂对全氟辛酸在土壤中迁移的影响

碳氟型表面活性剂全氟辛酸(Perfuorooctanoic Acid,PFOA)的大量使用导致其与各类碳氢表面活性剂广泛共存于土壤-地下水环境中,对人体健康和生态安全存在潜在威胁.通过柱实验探究不同离子强度条件下(1.5 mmol·L^(-1)和30mmol·L^(-1)),非离子型碳氢表面活性剂烷基糖苷(Alkyl Polyglycoside,APG)及两性型碳氢表面活性剂十二烷基二甲基甜菜碱(Dodecyl Dimethyl Betaine,BS-12)对PFOA在两种饱和土壤中迁移行为的影响和作用机制.结果表明,APG能促进PFOA的迁移行为,其主控机制为APG与PFOA在土壤表面的竞争吸附作用;BS-12能通过对土壤表面负电荷的中和作用及疏水作用增强PFOA在土壤中的阻滞,抑制其迁移行为.因此,预测和评估PFOA在土壤中的迁移行为时,需考虑共存碳氢表面活性剂的影响.

β-环糊精对两亲聚合物黏度与分子量测定的影响

为探究β-环糊精(β-CD)的包合作用对两亲聚合物(丙烯酰胺、丙烯酸、十六烷基烯丙基氯化铵三元共聚物APC_(16))黏度及黏均分子量的影响,通过流变仪研究了β-CD包合APC_(16)溶液的黏度变化规律及影响因素,采用乌氏黏度计测定了APC_(16)包合体系的特性黏数,进而准确计算出无分子间相互作用下APC_(16)的黏均分子量。结果表明,在45℃、矿化度为3×10^(4)mg/L的条件下,β-CD与APC_(16)物质的量比为1∶2时,APC_(16)溶液的临界缔合浓度升至5300 mg/L;β-CD与APC_(16)物质的量比为1∶1完全包合时,APC_(16)溶液的临界缔合行为消失。在完全包合比下,温度在25~90℃变化时,包合体系的黏流活化能小于APC_(16)溶液的黏流活化能。随NaCl浓度的增加,包合体系的黏度下降更加平缓,包合强度增强。据此,可以应用β-CD包合作用消除疏水缔合来测定两亲聚合物的黏均分子量。单一APC_(16)的黏均分子量为537×10^(4)Da、部分水解聚丙烯酰胺(HPAM)的黏均分子量为1292×104Da。当β-CD与APC_(16)物质的量比为1∶1、2∶1时,APC_(16)的黏均分子量分别为341×10^(4)、358×10^(4)Da。当β-CD与HPAM物质的量比为1∶1和2∶1时,HPAM的黏均分子量分别为1223×10^(4)、1272×10^(4)Da。HPAM的黏均分子量在包合前后的测定结果一致,证实β-CD包合法测定两亲聚合物分子量的有效性,为两亲聚合物疏水作用对黏度贡献和分子量测定提供新方法。

阳离子两亲性共聚物在有机鞣革复鞣中的应用

通过自由基聚合反应制备了阳离子两亲性共聚物(PSD),并将其用于TWS有机鞣革的复鞣。动态光散射和扩散波谱结果表明,PSD在水中的聚集程度随着pH提高、温度降低及浓度提高而增大。故选择pH 4、温度40℃的工艺条件用PSD对有机鞣革复鞣。PSD可渗透至有机鞣革的原纤维层级并形成疏水薄膜,从而显著提高坯革整体的疏水性,动态防水透水时间从0.14 min提高至10~20 min。此外,PSD促进了有机鞣革对阴离子加脂剂的吸收,吸收率从88.5%提高至93.7%。PSD用量越大,坯革的疏水性和增厚率提高而柔软度下降。综上,将阳离子两亲性共聚物应用于有机鞣革的复鞣能够提高成革的综合性能,这有助于发展完善无铬有机鞣制体系,制造高性能无金属生态皮革。

均聚物的添加对棒/线两亲性嵌段共聚物溶液自组装的影响

为了明晰均聚物对棒/线嵌段共聚物聚集行为的影响,利用实空间求解的格子自洽场方法,研究柔性均聚物和线/棒/线两亲性对称三嵌段共聚物溶液混合体系的自组装行为.格子自洽场方法通过链传播子和格子的各向异性近似处理分子链刚性,这使得该方法在计算速度方面有显著优势.模拟结果表明,均聚物对胶束结构重排行为的影响依赖于疏水棒嵌段长度,这源于棒嵌段长度的改变一定程度上影响了胶束破碎/融合的实现.研究还发现,均聚物的添加稳定了胶束重排过程中胶束结构的变化.本文的结果有助于进一步理解以刚性嵌段为核心胶束的生长机制,为相关的实验设计和材料应用提供理论指导.

Enhanced stability of nitrogen-doped carbon-supported palladium catalyst for oxidative carbonylation of phenol

Enhancing the stability of supported noble metal catalysts emerges is a major challenge in both science and industry.Herein,a heterogeneous Pd catalyst(Pd/NCF)was prepared by supporting Pd ultrafine metal nanoparticles(NPs)on nitrogen-doped carbon;synthesized by using F127 as a stabilizer,as well as chitosan as a carbon and nitrogen source.The Pd/NCF catalyst was efficient and recyclable for oxidative carbonylation of phenol to diphenyl carbonate,exhibiting higher stability than Pd/NC prepared without F127 addition.The hydrogen bond between chitosan(CTS)and F127 was enhanced by F127,which anchored the N in the free amino group,increasing the N content of the carbon material and ensuring that the support could provide sufficient N sites for the deposition of Pd NPs.This process helped to improve metal dispersion.The increased metal-support interaction,which limits the leaching and coarsening of Pd NPs,improves the stability of the Pd/NCF catalyst.Furthermore,density functional theory calculations indicated that pyridine N stabilized the Pd^(2+)species,significantly inhibiting the loss of Pd^(2+)in Pd/NCF during the reaction process.This work provides a promising avenue towards enhancing the stability of nitrogen-doped carbon-supported metal catalysts.

DNA-有机分子两亲体自组装的研究进展

DNA-有机杂化两亲体在水溶液中可以自组装成各种形态,调节其自组装形态和大小通常需要改变分子内部结构,或改变组装条件和方法。因此,获得具有单一形态或尺寸变量的聚集体是一个巨大的挑战。近年来,有学者首次提出了一种新的框架引导组装策略,即引导两亲体沿着锚定在框架上的疏水性基团聚集,最终按照预先设计的框架形成具有一定形状和均匀大小的形态。该策略突破了传统组装方法的限制,使制备具有可编程几何形状和尺寸的聚集体成为可能,为构建纳米结构提供了新的思路和方法,并在纳米科学和生物医学方面具有潜在的应用前景。

NOVEL AMPHIPHILIC FLUORESCENT GRAFT COPOLYMER: SYNTHESIS, CHARACTERIZATION AND ENCAPSULATION OF A HYDROPHOBIC AGENT

Novel amphiphilic fluorescent graft copolymer （PVP-PyAHy） was successfully synthesized by the free radical copolymerization of hydrophobic monomer N-（1-pyrenebutyryl）-N＇-acryloyl hydrazide （PyAHy） with hydrophilic precursor polymers of vinyl-functionalized poly（N-vinylpyrrolidone） （PVP） in DMF. The copolymer is amphiphilic and has intrinsic fluorescence. FT-IR, ^1H-NMR, TEM, gel permeation chromatography-multi-angle laser light scattering, UV-Vis spectroscopy and fluorescence spectroscopy were used to characterize this copolymer. The TEM observation shows that the copolymer PVP-PyAHy forms micelles in aqueous solution. Results of fluorometric measurements illustrate that the critical micelle concentration （CMC） value of PVP-PyAHy in aqueous solution is about 0.90 mg/mL. To examine the encapsulation ability of the copolymer in aqueous media, methyl yellow was employed as a model hydrophobic agent. The loading level of the polymer to methyl yellow is 8.8 mg/g. The cytotoxicity assays for Madin Darby Canine Kidney （MDCK） cells shows good biocompatibility of PVP-PyAHy in vitro. These results suggest the potential of this copolymer PVP-PyAHy as drugs delivery carrier and fluorescent tracer.

Amphiphilic sodium alginate-vinyl acetate microparticles for drug delivery

To overcome the fast or burst release of hydrophilic drugs from hydrophilic alginate-based carriers,hydrophobic molecule(vinyl acetate,VAc)was grafted on alginate(Alg),which was further used to prepare drug carriers.Amphiphilic Alg-g-PVAc hydrogel beads were firstly prepared by emulsification/internal gelation technique for the loading of bovine serum albumin(BSA).Then,chitosan was coated on the surface of beads to form novel amphiphilic Alg-g-PVAc/chitosan(Alg-g-PVAc/CS)microcapsules.The BSA-loading amphiphilic Alg-g-PVAc/chitosan(Alg-g-PVAc/CS)microcapsules display similar morphology and size to the hydrophilic alginate/chitosan(AC)microcapsules.However,the drug loading and loading efficiency of BSA in Alg-g-PVAc/CS microcapsules are higher,and the release rate of BSA from Alg-g-PVAc/CS microcapsules is slower.The results demonstrate that the introduction of hydrophobic PVAc on alginate can effectively help retard the release of BSA,and the higher degree of substitution is,the slower the release rate is.In addition,the complex membrane can also be adjusted to delay the release of BSA.As a whole,amphiphilic sodium alginate-vinyl acetate/CS microparticles could be developed for macromolecular drug delivery.

Synthesis and characterization of H-type amphiphilic liquid crystalline block copolymers by ATRP

H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization （ATRP）. Macroinitiators prepared by the esterification between poly（ethylene oxide） （PEG） and 2,2-dichloroacetyl chloride were utilized to initiate the polymerization of 6-[4-（4-ethoxyphenylazo）phenoxy]hexyl rnethacrylate （M6C）. The resulting macroinitiators and block copolymers were characterized by ^1H NMR, gel permeation chromatography （GPC）. Polarizing optical microscopy （POM） and differential scanning calorimetry （DSC） preliminarily revealed the liquid crystalline property of these block copolymers. This series of liquid crystalline block copolymers are promising in some areas, such as optical data storage, optical switch, and molecular devices.

SYNTHESIS OF AMPHIPHILIC COMB-SHAPED COPOLYMERS USED FOR SURFACE MODIFICATION OF PVDF MEMBRANES

The synthesis of a novel amphiphilic comb-shaped copolymer consisting of a main chain of styrene-(N-(4- hydroxyphenyl) maleimide)(SHMI) copolymer and poly(ethylene glycol) methyl ether methacrylate(PEGMA) side groups was achieved by atom transfer radical polymerization(ATRP).The amphiphilic copolymers were characterized by ~1H-NMR, Fourier transform infrared(FTIR) spectroscopy and gel permeation chromatography(GPC).From thermogravimetric analysis (TGA),the decomposition temperature of SHMI-g-PEGMA is lower ...

Structural Multiplicity of Monomers of an Amphiphilic Porphyrin at the Outer Surface of CTAB Micelle

A synthesized amphiphilic porphyrin, 5,10,15-tri(p-hydroxyphenyl)-20-(p-hexadecyloxyphenyl) porphyrin, can take a transfer process for the porphyrin moiety from the inner core to the outer surface laver of cetyltrimethylammonium bromide (CTAB) micelle. The increasing of FWHH of the Sorer band was attributed to the multiplicity of porphyrin monomers related with deprotonation degree, arrangement, orientation, and position of porphyrin moiety at the surface al ea rather than the aggregates associated with irregular orientation of neighboring porphyrins.

STUDIES ON SELF-ASSOCIATIVE BEHAVIOR OF A NOVEL CATION AMPHIPHILIC POLYMER

A novel associating polymer P(AEBA) was synthesized by radical polymerization of the cationic amphiphilic monomer,4-(2-(acryloyloxy)ethoxy)benzyl tri-ethyl ammonium bromide(AEBA),in aqueous solutions.P(AEBA) displays a strong tendency for self-association in aqueous solutions and is sensitive to the external stimulation such as added salt.The associative properties and morphologies of P(AEBA) were studied by fluorescnece probe technique,viscometry and TEM.In dilute salt-free solutions P(AEBA) behaves as pol...

AMPHIPHILIC STAR-BLOCK COPOLYMERS BY IODIDE-MEDIATED RADICAL POLYMERIZATION

Amphiphilic star-block copolymers composed of polystyrene and poly（acrylic acid） were synthesized by iodide- mediated radical polymerization. Firstly, free radical polymerization of styrene was carried out with AIBN as initiator and 1,1,1-trimethyolpropane tri（2-iodoisobutyrate） as chain transfer agent, giving iodine atom ended star-shaped polystyrene with three arm chains, R（polystyrene）3. Secondly, tert-butyl acrylate was polymerization using polystyrene obtained as macro-chain transfer agent, and star-block copolymer, R（polystyrene-b-poly（tert-butyl acrylate））3 with controlled molecular weight was obtained. Finally, amphiphilic star-block copolymer, R（polystyrene-b-poly（acrylic acid））3 was obtained by hydrolysis of R（polystyrene-b-poly（tert-butyl acrylate））3 under acidic condition.

CONTROLLED SYNTHESIS OF AMPHIPHILIC BLOCK POLYMERS HAVING GLUCOSE RESIDUES AND THEIR STRUCTURE FORMATION

Vinyl ether (VE)-based amphiphilic block copolymers with D-glucose residues as hydrophilicpendants were synthesized by CH_3 CH(OiBu)Cl/ZnI_2-initiated sequential living cationic copolymerization of3-O-(vinyloxy)ethyl-1, 2:5, 6-di-O-isopropylidene-D-glucofuranose (IGVE) and isobutyl VE (IBVE ) andsubsequent deprotection. The precursor block copolymers had a narrow molecular weight distribution(M_w/M_n～1.1) and a controlled segmental composition. The solubility characteristics of the amphiphiliccopolymer depended strongly on composition. Their solvent-cast thin films were examined, under atransmission electron microscope, and could be seen to exhibit various microphase-separated surfacemorphologies such as spheres, cylinders, and lamellae, depending on composition. The amphiphiliccopolymers with the appropriate segmental composition were found to form a stable monolayer at the air-water interface, which was successfully transferred onto a substrate by the Langmuir-Blodgett (LB)technique. The layered strucfure of the built-up LB films was controlled by blending the homopolymer.

Amphiphilic Poly (3-Hydroxy Alkanoate)s: Potential Candidates for Medical Applications

Poly (3-hydroxy alkanoate)s, PHAs, have been very attractive as biomaterials due to their biodegradability and biocompatibility. These hydrophobic natural polyesters, PHAs, need to have hydrophilic character particularly for drug delivery systems. In this manner, poly (ethylene glycol) (PEG) and hydrophilic functional groups such as amine, hydroxyl, carboxyl and sulfonic acid have been introduced into the PHAs in order to obtain amphiphilic polymers. This review involves in the synthesis and characterization of the amphiphilic PHAs.

SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC GRAFT COPOLYMER CONTAINING MICROPHASE SEPARATED AND LONG POLY(ETHYLENE OXIDE) SIDE CHAIN STRUCTURES

Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called 'selective dissolution', the well-defined structure of the purified copolymers was confirmed by IR, ~1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed 'comb- model' was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.

New modular platform based on multi-adjuvanted amphiphilic chitosan nanoparticles for efficient lipopeptide vaccine delivery against group A streptococcus

An effective vaccine against group A streptococcus(GAS)is highly desirable for definitive control of GAS infections.In the present study,two variants of amphiphilic chitosan nanoparticles-based GAS vaccines were developed.The vaccines were primarily composed of encapsulated KLH protein(a source of T helper cell epitopes)and lipidated M-protein derived B cell peptide epitope(lipoJ14)within the amphiphilic structure of nanoparticles.The only difference between themwas one of the nanoparticles vaccines received additional surface coating with poly(I:C).The formulated vaccines exhibited nanosized particles within the range of 220–240 nm.Cellular uptake study showed that nanoparticles vaccine without additional poly(I:C)coating has greater uptake by dendritic cells and macrophages compared to nanoparticles vaccine that was functionalized with poly(I:C).Both vaccines were found to be safe in mice and showed negligible cytotoxicity against HEK293 cells.Upon immunization in mice,both nanoparticle vaccines produced high antigen-specific antibodies titres that were regulated by a balanced Th1 and Th2 response compared to physical mixture.These antibodies elicited high opsonic activity against the tested GAS strains.Overall,our data demonstrated that amphiphilic chitosan nanoparticles platform induced a potent immune response even without additional inclusion of poly(I:C).

MORPHOLOGICAL TRANSITION BETWEEN VESICLES AND TUBULES FOR A GLYCOPOLYMER-CONTAINING AMPHIPHILIC DIBLOCK COPOLYMER IN AQUEOUS SOLUTIONS

The morphological transition of molecular assemblies in aqueous solutions for a new amphiphilic diblock copolymer induced by changing the initial solvent conditions was studied by transmission electron microscopy (TEM). The copolymer was polystyrene(77)-b-poly[2-(beta -D-glucopyranosyloxy)ethyl acrylate (6)] (PSt(77)-b-PGEA(6)) and the solvent was a mixture of DMF and THF. PSt(77)-b-PGEA(6) yields vesicles and tubules when it is initially dissolved in THF and DMF respectively. The morphological transition between vesicles and tubules can be achieved by simply varying the amounts of THF and DMF, or changing the temperature at which the aggregates were prepared.