一种含假芪型偶氮生色团两亲性嵌段共聚物的合成与表征

利用原子转移自由基聚合（ATRP）合成了一种新型的含假芪型偶氮生色团的两亲性嵌段共聚物P（HEMA-b-6CNAzo）。首先,采用ATRP引发剂引发三甲基硅保护的羟乙基甲基丙烯酸酯（HEMA—TMS）聚合,得到大分子引发剂P（HEMA—TMS）;接着进一步引发单体甲基丙烯酸6-（N_甲基苯胺基）己酯进行ATRP反应,得...     

Synthesis,crystal structure,and characterization of [Nd(tcph)(Htcph)(H2O)5]

A lanthanide complex [Nd(tcph)(Htcph)(H₂O)₅] (1) (H₂tcph?=?tetrachlorophthalic acid) has been characterized by X-ray single crystal diffraction, elemental analysis, IR, UV-Vis and fluorescence spectra. In the title complex, Nd³⁺ is coordinated by two tetrachlorophthalic acid ligands in a bidentate chelated pattern. Furthermore, the complex contains infinite chains linked by hydrogen bonds.     

Supramolecular networks with 1-substituted benzotriazole ligands and transition metals

1-(2-Pyridyl)benzotriazole (L1) and 1-(4-pyridyl)benzotriazole (L2) with transition metal cations Co(II), Ni(II) and Cu(II) give four coordination complexes, [{Cu(L1)₂(H₂O)₂} · 2NO₃] (1), [{Co(L1)₂(H₂O)₂} · 2NO₃] (2), [Ni(L2)₂(NO₃)₂(H₂O)₂] (3), and [Cu₂(L2)₂(CH₃COO)₄] (4). In 1–4, different supramolecular frameworks are formed through hydrogen bonding and/or π–π interactions.     

中间嵌段为亲水性的BAB型三嵌段共聚物水溶液中初级聚集体的二次聚集行为研究

采用TEM和AFM研究了PS(聚苯乙烯)₄₃-b-PEO(聚氧乙烯)₄₅-b-PS₄₃和PS₃₉-b-P4VP(聚4-乙烯基吡啶)₉₈-b-PS₃₉三嵌段共聚物在水介质中的球形胶束、囊泡和蠕虫状胶束之间的二次聚集行为.实验发现,初级聚集体的二次聚集具有不同的复杂程度.对称性的初级聚集体,如球形胶束和囊泡,其二次聚集表现出球形对称性;而非对称性初级聚集体(如蠕虫状胶束)二次聚集开始倾向于非对称性.BAB型的嵌段设计有利于初级聚集体的二次聚集发生.     

Effects of cationic head groups of ionic liquid on micellization in aqueous solution of PEO-PPO-PEO triblock copolymer

The interaction of ionic liquids (ILs) with non-ionic triblock copolymer, Pluronic® P123 in aqueous solutions has been investigated using DLS, surface tension, and viscosity measurements. The addition of ILs increased the Critical Micelle Concentration (CMC) of P123, which appears to be logistic. As the added IL enhances the solubility of PPO moiety (and PEO), which makes them to behave like a more hydrophilic block copolymer that would be micellized at high copolymer concentration. The DLS data is in good agreement to the results observed from surface tension measurements. Viscosity results show the propensity in micellar size reduction upon addition of ILs, and hence, intrinsic viscosity decreases as compared to pure P123 aqueous solution. The results are studied and discussed as a function of cationic head groups of N-octyl-pyridinium/imidazolium chloride based ILs.     

Prediction of cathodic E1/21 and E1/22 values for viologen-containing conjugated unimers and dimers from calculated pKb values of the aromatic substituents

A library of 18 conjugated, rod-like compounds with either one or two viologen residues were synthesized and characterized electrochemically. Containing up to 8 aromatic/heterocyclic rings in conjugation, the members of the library differ in the substitution pattern of electron-withdrawing or -donating groups on the aromatic substituents of the viologen units. The first and second half-wave potentials of each member were found to be linearly correlated with the calculated pK_b values of the aromatic end-groups. This relationship will enable the half-wave potentials of related, novel, substituted viologen species to be predicted using a simple, empirical formula.     

Supramolecular solvent-based microextraction of ochratoxin A in raw wheat prior to liquid chromatography-fluorescence determination

A supramolecular solvent made up of reverse micelles of decanoic acid, dispersed in a continuous phase of THF:water, was proposed for the simple, fast and efficient microextraction of OTA in wheat prior to liquid chromatography-fluorescence determination. The method involved the stirring of 300 mg-wheat subsamples (particle size 50 μm) and 350 μL of supramolecular solvent for 15 min, subsequent centrifugation for 15 min and the direct quantitation of OTA in the extract, previous 5.7-fold dilution with ethanol/water/acetic acid (49.5/49.5/1), against solvent-based calibration curves. No clean-up of the extracts or solvent evaporation was needed. Interactions between the supramolecular solvent and major matrix components in the wheat (i.e. carbohydrates, lipids and proteins) were investigated. The reverse micelles in the extractant induced gluten flocculation but only in the coacervation region of lower analytical interest (i.e. at percentages of THF above 11%). The quantitation of OTA was interference-free. Representativity of the 300 mg-wheat subsamples was proved by analysing a reference material. OTA recoveries in wheat ranged between 84% and 95% and the precision of the method, expressed as relative standard deviation, was 2%. The quantitation limit of the method was 1.5 μg kg⁻¹ and was below the threshold limit established for OTA in raw cereals by EU directives (5.0 μg kg⁻¹). The method developed was validated by using a certified reference material and it was successfully applied to the determination of OTA in different wheat varieties from crops harvested in the South of Spain. OTA was not detected in any of the analysed samples. This method allows quick and simple microextraction of OTA with minimal solvent consumption, while delivering accurate and precise data.     

Block Copolymer Supported Gold Nanoparticles Assemblies with Exposed Gold Surface

Polymer-involved nanoparticles or nanoparticle assemblies are now facing a crossroad, where the exposure of nanoparticle and multiple nanoparticles cannot be obtained at the same time. Therefore, a new series of nanoparticle clusters is synthesized, where multiple gold nanoparticles assemble with amphiphilic block copolymers supporting inside. The exposure of gold nanoparticles of the structure is confirmed and increases the reduction rate of 4-nitrophenol by 60%. The assemblies can also be used as surface enhanced Raman scattering(SERS) probes with an enhancement factor(EF) as high as 3×10³.     

Self-assembly in magnetic supramolecular hydrogels

Most recent advances in the synthesis of supramolecular hydrogels based on low molecular weight gelators (LMWGs) have focused on the development of novel hybrid hydrogels, combining LMWGs and different additives. The dynamic nature of the noncovalent interactions of supramolecular hydrogels, together with the specific properties of the additives included in the formulation, allow these novel hybrid hydrogels to present interesting features, such as stimuli-responsiveness, gel-sol reversibility, self-healing and thixotropy, which make them very appealing for multiple biomedical and biotechnological applications. In particular, the inclusion of magnetic nanoparticles in the hydrogel matrix results in magnetic hydrogels, a particular type of stimuli-responsive materials that respond to applied magnetic fields. This review focuses on the recent advances in the development of magnetic supramolecular hydrogels, with special emphasis in the role of the magnetic nanoparticles in the self-assembly process, as well as in the exciting applications of these materials.     

Direct synthesis of Poly(Ԑ-Caprolactone)-block-poly (glycidyl methacrylate) copolymer and its usage as a potential nano micelles carrier for hydrophobic drugs

Ring-opening (ROP) and enzymatic copolymerization (ECP) are among the most widely used approaches for synthesizing copolymers of polycaprolactone (PCL). It involves multiple-step reactions and the utilization of enzymes that make the process a lot more complicated, time consuming, and expensive. Atom transfer radical polymerization (ATRP) has been adopted to synthesize a novel amphiphilic copolymer in our study. The study presents a method to eliminate the ROP/ECP multiple steps in monomer polymerization thus making the process simpler and smoother. The synthesis of cationic polymer micelles copolymer of PCL-PGMA (polycaprolactone grafted poly glycidyl methacrylate) was carried out using direct functionalization of hydroxy group in crude PCL to achieve a higher degree of functionalization, i.e., 12.8% for macroinitiator. FTIR and ¹H-NMR confirmed the successful synthesis of the copolymer with better control over the molecular weight with a PDI (1.84). DSC and XRD results showed the reduction of crystallinity by 86.81%, making copolymer more compatible for drug delivery application. The synthesized copolymer was further converted to nano-micelles drug carrier having an average size of 96.08 ± 21.22 nm. The drug encapsulation efficiency achieved was 60.0 ± 1.7%, and nano-micelles rendered a slow and controlled release of naproxen with long-term storage stability.