Initially colorless and transparent,the sucrose solution exhibited a stunning array of colors when viewed through a polarizer.This study utilized polarization characteristics to explore the variations in beam split capacity among different sucrose solution concentrations,while also tracking the hydrolysis process of sucrose under acidic conditions.The paper further elucidates the scientific principles underlying these experimental phenomena.

冷冻聚合是一种新发展的聚合反应实施方法,其聚合温度低于反应介质的凝固点,聚合场所为冻结聚合体系中的液相微区,液相微区的体积百分数约为10％.因为聚合温度低、液相微区的单体浓度很高,所以冷冻聚合是制备高/超高分子量聚合物的有效方法.本实验分别实施丙烯酰胺和丙烯酸的冷冻聚合,通过改变冷冻聚合条件调控聚合物的分子量,使用稀溶液黏度法测定所得聚合物的分子量.通过该实验,帮助学生理解自由基聚合分子量控制的基本原理,学会灵活运用Mayo方程,引导学生关注实验细节、掌握实验技巧、学会实验设计.

: Through the introduction of several kinds of polymer materials which play an important role in COVID-19 epidemic prevention, the basic knowledge of the related polymers is popularized. In particular, the unique long-chain structure and excellent properties different from small molecular materials, including light weight, flexibility, easiness in processing, easy regulation of properties, are introduced.

Recently, investigation on two-dimensional (2D) organic polymers has made great progress, and conjugated 2D polymers already play a dynamic role in both academic and practical applications. However, a convenient, noninterfacial approach to obtain single-layer 2D polymers in solution, especially in aqueous media, remains challenging. Herein, we present a facile, highly efficient, and versatile "1D to 2D" strategy for preparation of free-standing single-monomer-thick conjugated 2D polymers in water without any aid. The 2D structure was achieved by taking advantage of the side-by-side self-assembly of a rigid amphiphilic 1D polymer and following topochemical photopolymerization in water. The spontaneous formation of single-layer polymer sheets was driven by synergetic association of the hydrophobic interactions, π-π stacking interactions, and electrostatic repulsion. Both the supramolecular sheets and the covalent sheets were confirmed by spectroscopic analyses and electron microscope techniques. Moreover, in comparison of the supramolecular 2D polymer, the covalent 2D polymer sheets exhibited not only higher mechanical strength but also higher conductivity, which can be ascribed to the conjugated network within the covalent 2D polymer sheets.

A new kind of accordion-type chain-folded poly(ester urea) was designed and synthesized by polyesterfication of the monomer with dicarboxylic groups, 4,4 '-(carbonyldiimino) dibenzoic acid and the monomer with dibromo groups, 3,5-bis(bromoalkoxyl) benzoate in polar solvents at ambient temperature. The kinetics of the polyesterification reaction was monitored by proton nuclear magnetic resonance (H-1-NMR) tracking. It was found that the rate of the polyesterification was highly dependent on the length of the side alkyl chains in the monomer bearing dibromine groups. A shorter alkyl chain was more favorable for the polyestification owing to the different solubility of the monomers, the monomer bearing a long alkyl chain was more soluble. The number average molecular weight and the structure of the obtained poly(ester urea) were characterized by (HNMR)-H-1 and Fourier transform infrared spectroscopy (FTIR). The number average molecular weight of the poly(ester urea) was measured to be about 2 x 10(4). Differential scanning calorimetry (DSC) result showed that the melting point of the poly(ester urea) was 57 degrees C, suggesting that the presence of crystallinity in the poly(ester urea). While the result from thermogravimetric analysis (TGA) displayed that the poly(ester urea) was highly thermalstable with an obvious thermal degradation around 407 degrees C. Because of the presence of the hydrogenbond between the urea groups and pi-pi interaction between the phenyl units, selfassembly behavior of the poly(ester urea) in a mixed organic solvent of chloroform and methanol was characterized by transmission electron microscope (TEM). The result revealed that lamellar aggregates formed in the poly(ester urea) after selfassemble for 4 h. However, the lamellar aggregates ultimately transformed into thermodynamically stable vesicles after standing for 3 days. The thickness of the vesicle wall was estimated to be about 7 nm, close to the calculated size of the folded chain. Moreover, the result of Xray diffraction (XRD) confirmed the presence of ordered structure in the polymer, demonstrating further that the poly(ester urea) adopts a chainfolded conformation.

2,4,6-Tri(dimethylaminomethyl)-phenol was synthesized as a trifunctional moiety and incorporated onto poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) to obtain a novel quaternary ammonium functionalized PPO (PPO-TQA). Membranes of the polymer were fabricated and exhibited high conductivity, a low swelling ratio and water uptake.

A facile one pot strategy for the preparation of linear and hyperbranched polyacrylates has been successfully developed by the combination of in situ esterification of acrylic acid with halogenated compounds promoted by 1,1,3,3-tetramethylguanidine (TMG) and RAFT polymerization.

We designed and synthesized a novel poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with imidazolium-functionalized aromatic side chains by the reaction of imidazole-functionalized PPO and methyl iodide, and then prepared the acid doped PPO membrane by immersing the polymer membrane in phosphoric acid (PA). To achieve a high acid doping level and a high dimensional stability, the cross-linked membranes were prepared by the reaction of the imidazole groups of the polymer and 1,4-bis(bromomethyl) benzene. The PA content, area swelling, and tensile strength of the non-crosslinked and the crosslinked membranes doped with a H3PO4 solution were measured. The results showed that the crosslinked membrane with a PA content of 438% possessed the highest conductivity of 54 mS cm−1 at 140 °C with high dimensional stability and high tensile strength. Moreover, no shape change of the membranes was observed in 15 days in a Fenton solution containing 3% H2O2 and 4 ppm Fe2+ at 80 °C, indicating a high oxidative stability. Therefore, this new polymer can be considered as a promising candidate for preparing a high temperature proton exchange membrane for use in fuel cells.

A new ABA triblock copolymer (QPPO-PAES-QPPO) was successfully synthesized by combining one block of poly(arylene ether sulfone)s (B, PAES) and two blocks of quaternary ammonium functionalized poly(2,6-dimethyl-1,4-phenylene oxide) (A, QPPO). Membranes of the triblock copolymer with distinct nanophase separation showed high performance.

A facile strategy for the synthesis of guanidinium-functionalized poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with improved alkaline stability was developed by the reaction of bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) with 2-benzyl-1,1,3,3-tetramethylguanidine (BTMG). The chemical structure of guanidinium-functionalized polymers was confirmed by 1H NMR and FT-IR spectroscopy. A crosslinked membrane of the polymer which have an ionic exchange capacity (0.80 mmol/g) and low swelling ratio (<15%) was fabricated. The ionic conductivity of the cross-linked membrane was higher than 1.0×10−2 S cm−1 at room temperature and 5.1×10−2 S cm−1 at 70 °C. The microstructure of hydrophobic/hydrophilic phase separation of the film was observed by transmission electron microscopy (TEM). Finally, the alkaline stabilities of model guanidiniums and the cross-linked membrane were evaluated respectively. The results showed that the bulky guanidinium cation exhibited higher alkaline stability due to the steric hindrance of the substituents, and the cross-linked membrane remain the ionic conductivity of 4.2×10−2 S cm−1 at 70 °C after being immersed in 1 M NaOH/D2O solution at 60 °C for 2 days. The mechanical properties of the membranes were also measured before and after 2 days of stability testing. All results suggest that this alkaline anion exchange membrane (AAEM) functionalized by bulky guanidinium groups could be considered as a promising candidate for polymer electrolyte membrane in alkaline fuel cells.

Esterifications of poly(methacrylic acid) (PMAA) and poly(acrylic acid) (PAA) have been investigated with a wide variety of halogenated compounds such as iodide, bromide, and chloride using 1,1,3,3-tetramethylguanidine as a promoter. The results demonstrate that the poly(meth)acrylates can be obtained with an excellent degree of esterification at room temperature. The influence of solvent, reaction conditions, and halogenated compounds on the esterification reaction was examined. It was found that polar solvents, such as dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF), are favorable for the esterification and high degree of esterification can be achieved in a short time. Moreover, the esterification reaction of PMAA has been successfully performed in an aqueous solution of DMSO, which indicates that the solvent does not necessarily have to be dried for this reaction. Primary and secondary halogenated compounds can successfully react with PMAA or PAA, while tertiary halogenated compounds fail to react. In addition, combining this esterification reaction with atom transfer radical polymerization (ATRP), macromonomers were conveniently prepared by the reaction of halogen-capped polymers with methacrylic acid under mild conditions.

Linear triblock copolymers of poly(N-isopropylacrylamide) (PNIPAM) and poly(ethylene glycol) (PEG) with two azide groups at both block junctions (PNIPAM-N3-PEG-N3-PNIPAM) are click reacted with dipropargyl oxalylate under high polymer concentration (250 g/L). Benefiting from rapid feature of alkyne-azide click reaction and spatial shielding of PNIPAM end blocks, PEG center block of PNIPAM-N3-PEG-N3-PNIPAM remains separated although PNIPAM end blocks keep in contact under this high concentration. Therefore, PNIPAM-N3-PEG-N3-PNIPAM undergoes self-cyclization at block junctions to form tadpole-shaped architecture while N3-PEG-N3 without PNIPAM end blocks inter-connects linearly. The influence of block lengths of PEG and PNIPAM on the unusual cyclization under high polymer concentration is studied.

Living/controlled radical copolymerization of hexafluoropropylene and butyl vinyl ether has been successfully achieved at room temperature under Co-60 gamma-ray irradiation in the presence of ethyl 2-(ethoxycarbonothioylthio) acetate. The copolymer end-capped with a sulfonic acid group has been prepared by oxidation of the xanthate end group.

Multiwalled carbon nanotubes functionalized with an imidazolium-type ionic liquid polymer, PIL(BF4)–MWCNTs, have been successfully prepared via in situ free radical polymerization of 1-vinyl-3-methylimidazolium iodide ([VMIm][I]) and then blended with poly(2,6-dimethyl-1,4-phenylene oxide) containing imidazolium groups (PPO–MIm) in solution to fabricate composite membranes. The composite membranes were characterized by scanning electron microscopy (SEM) and the SEM images of the membranes show that the PIL(BF4)–MWCNTs can be homogeneously dispersed in the PPO–MIm matrix. The conductivity and mechanical properties of the composite membranes were examined. It was demonstrated that the incorporation of the PIL(BF4)–MWCNTs into the membranes of PPO–MIm can increase both conductivity and mechanical properties. The composite membrane containing 0.3 wt% of PIL(BF4)–MWCNTs (P(0.3)) exhibits a dramatic enhancement in ionic conductivity (95.3%) and tensile strength (82.9%) in comparison with the membrane without PIL(BF4)–MWCNTs. Therefore, this research demonstrates that the incorporation of functionalized carbon nanotubes is a facile and useful strategy for improving both ionic conductivity and mechanical properties of alkaline polymer electrolyte membranes.

A novel well-defined amphiphilic fluorescent polymer containing asymmetric perylene bisimide was designed and synthesized by combining reaction of perylene anhydride with amino functional polyhedral oligomeric silsesquioxane (POSS) and atom transfer radical polymerization (ATRP) of N-isopropylacrylamide (NIPAM). All the intermediate and final products were characterized by NMR, Fourier transform infrared spectroscopy (FT-IR), elemental analyses, and gel permeation chromatograph (GPC). Self-assembly of the amphiphilic polymers was investigated in aqueous solution and POSS-containing hybrid nanoparticles were obtained and characterized by dynamic laser light scattering (DLS) and transmission electron microscopy (TEM). The novel hybrid nanoparticles exhibit attractive high red fluorescence at 645 nm due to the significant effect of the bulky POSS moieties. Moreover, based on the thermoresponsive PNIPAM coronas, the fluorescence intensity of the self-assembled hybrid nanoparticles can be further enhanced and tuned by changing temperature.

Alcohols have been demonstrated to be efficient reducing agents for AGET-ATRP for the first time. Well-controlled polymerizations have been successfully achieved with the typical characteristics of "living"/controlled radical polymerization.

Three novel conjugated polymers based on 2,2'-biimidazole have been successfully designed and synthesized through the Suzuki coupling reactions, and their fluorescence sensing ability to metal ions and anions was investigated. The emission of the two polymers with hydrophilic side chains can be efficiently quenched by Cu2+ through a photoinduced electron transfer process. Moreover, the polymer Cu2+ complexes exhibit excellent "turn on" sensing properties for detection of pyrophosphate (PP anion. These complex sensors possess high selectivity avoiding the interference from other anions, very fast response (less than 3 min) to PPi, and the detection limit of about 0.17 ppm. In addition, the linear detection range of PPi can be tuned conveniently by changing the amount of Cu2+ ions. Thus, the conjugated polymers can be used as a novel fluorescent sensing platform, and this work provides a new strategy for the development of PPi sensors.

Well-defined diblock copolymer based on polyhedral oligomeric silsesquioxane (POSS) was synthesized by atom transfer radical polymerization (ATRP) using POSS/PMMA-Cl as a macroinitiatior. POSS/PMMA-Cl was prepared by POSS-Cl initiating the polymerization of MMA in the presence of CuCl, 2, 2, - bipyridine at 110 °C. The structure of the block copolymer had been characterized by FTIR, 1H NMR and GPC, which all agreed well with the theoretical values. XRD measurements revealed that POSS molecules were successfully monodispered in the hybrid composite.

The interactions between SWNTs(single-walled carbon nanotubes) and functionalized SAMs(self-assembled monolayers) in aqueous solution were simulated through the molecular dynamic method.The SAMs were functionalized by the functional groups of proteins.The simulation results showed that the interaction energy between SWNTs and the charged SAMs are zero because of the solvent effect of water molecules.The SWNTs have affinity with the uncharged SAMs,while the van der Waals interaction gives the dominant effect to the interaction energy.The analysis of the distance of the mass center also proved that the types and ionization states of the functional groups had a strong influence on the interactions between SWNTs and SAMs.The effective interaction distance between atoms of proteins and SWNTs was also validated.

A method of fabricating nanotemplate and nanowires by the anodization of bulk aluminum at room temperature is reported in this paper. Details of manufacturing processes as well as some in-depth discussions on the formation mechanism of nano pores with reference to the phenomena observed in experiments are presented. Effects of fabricating conditions such as the anodization time, temperature, current intensity, voltage and features of solutions, were studied in the experiments.