Fabrication of Gold Nano‐Structures with Azopolymer Templates

Fabrication of gold nano‐patterns has been demonstrated employing surface relief structures created on films of an azobenzene‐functionalized polymer as templates. The surface relief templates were photoinscribed on the azopolymer films in one‐step with two laser beams. Thin layers of gold were over‐coated on the polymer templates by thermal evaporation. Gold lines of a few hundred nanometer width were successfully fabricated by pyrolyzing the azobenzene polymer. Sub‐micron gold dots were also created. The resulting gold structures exhibited the same periodicity as the polymer templates.     

高分子模板调控不同形貌氧化亚铜的仿生合成

采用聚丙烯酰胺(PAM)为软模板,在CuSO4、Na2SO3体系中调控合成了片状、海胆状、一维线、针状聚集体氧化亚铜晶体。研究了不同浓度Cu2+、不同PAM含量及不同温度对晶体生长的影响。结果表明,PAM促使氧化亚铜异相成核,氧化亚铜形貌随PAM质量分数的变化而变化:当c(Cu2+)=0.5mol.L-1时,PAM质量分数为3.0%(常温引入体系),产物主要为片状晶体;PAM质量分数为1.0%、3.0%时(高温引入体系),分别获得一维线状、海胆状晶体;当Cu2+浓度为0.1 mol.L-1时,体系中高温引入质量分数3.0%的PAM,得到片层状晶体;当Cu2+浓度为0.3、0.4 mol.L-1时,得到针状聚集体氧化亚铜晶体。分别用X射线粉末衍射、冷场发射扫描电子显微镜和激光粒度仪对所制备的产品进行了表征。     

模板-聚合法Pd/Al2O3催化剂制备及其蒽醌加氢性能研究

以丙烯酸铵为模板剂,由油柱成型法制备了系列球形Al2O3载体,采用XRD、BET等分析测试手段对其晶体结构、比表面积、孔容和孔径分布进行了表征,结果表明,600℃焙烧的球形γ-Al2O3载体具有介孔结构,并且比表面较不使用模板剂的样品有大幅度增加。焙烧温度升至960℃得到δ-Al2O3,介孔结构消失,但由于结构记忆效应,载体的大表面特性得以保持。以δ-Al2O3为载体制备Pd/Al2O3催化剂,采用氢-氧滴定(HOT)方法测定发现,比表面的增加显著提高了Pd金属的分散度,从而大幅度提高了催化剂的蒽醌加氢活性,氢化效率最高可达10.5 g.L-1。     

Synthesis of a New Heteropolytopic Cryptand Through Schiff Base Condensation in the Presence of Ba(II) Ion

A new Schiff base cryptand (L) has been prepared via [2 + 2] condensation of 1,3,5-tris(2-formylphenoxymethyl)benzene (1) with 1,3,5-tris(aminomethyl)benzene trishydrochloride (2) in the presence of Ba(II) ion. The analytical data show that the Ba(II) cation is not retained by the product. Thus it seems that the role of the Ba(II) ion is to organize the transition state preceding the formation of the cryptand.     

Templating Irreversible Covalent Macrocyclization by Using Anions

Inorganic anions were used as templates in the reaction between a diamine and an activated diacid to form macrocyclic amides. The reaction conditions were found to perform the macrocyclization sufficiently slow to observe a template effect. A number of analytical methods were used to clarify the reaction mechanisms and to show that the structure of the intermediate plays a decisive role in determining the product distribution. For the macrocyclization under kinetic control, it was shown that the amount of a template, the conformational rigidity of building blocks, and the anion affinities of reaction components and intermediates are important parameters that one should take into consideration to achieve high yields.     

Metallogel Template Fabrication of pH‐Responsive Copolymer Nanowires Loaded with Silver Nanoparticles and Their Photocatalytic Degradation of Methylene Blue

Poly(N,N′‐methylenebisacrylamide–4‐vinylpyridine) (P(MBA‐4VP)) nanowires loaded with silver nanoparticles (Ag NPs) have been fabricated by silver metallogel template copolymerization, and subsequently, silver ions are reduced instead of the template being removed. Ag NPs with a diameter of 5–15 nm were dispersed throughout the core of P(MBA‐4VP) nanowires. The size and distribution of the formed Ag NPs could be finely controlled by reduction time. The pH sensitivity of P(MBA‐4VP) nanowires offers the possibility of Ag NP release from the nanowires under acidic conditions. The photocatalytic performance of the P(MBA‐4VP) nanowires loaded with Ag NPs was evaluated for the degradation of methylene blue (MB) under UV light irradiation. Their rate of degradation is dependent on the content and size of the Ag NPs, as well as the pH values of the MB solution. Moreover, the P(MBA‐4VP) nanowires loaded with Ag NPs exhibited high photostability, and the photocatalytic efficiency reduced by only 1.81 % after being used three times.     

[2]Catenane Synthesis via Covalent Templating

After earlier unsuccessful attempts, this work reports the application of covalent templating for the synthesis of mechanically interlocked molecules (MiMs) bearing no supramolecular recognition sites. Two linear strands were covalently connected in a perpendicular fashion by a central ketal linkage. After subsequent attachment of the first strand to a template via temporary benzylic linkages, the second was linked to the template in a backfolding macrocyclization. The resulting pseudo[1]rotaxane structure was successfully converted to a [2]catenane via a second macrocyclization and cleavage of the ketal and temporary linkages.     

Large-scale plasmonic-SERS templates by successive growth steps

This work presents the fabrication of large-scale tunable-plasmonic surface-enhanced Raman scattering (SERS) templates and investigates their Raman enhancement. Substrates for SERS were prepared by deposition of gold nanoparticles on a glass slide followed by their growth. A plasmon shift was observed upon growing due to the formation of elongated nanoparticles and their mutual coupling. The changes in particle size, shape and interparticle distances were indicated by SEM measurements. Surface-enhanced Raman spectra of Nile blue A at a very low concentration on top of a blocking layer were measured. The overall Raman enhancement is correlated with the number of growth steps. For excitation at 532 nm four growth steps lead to maximum enhancement. Better overlap of excitation laser and the plasmon resonances upon growing increased the enhancement until four steps while further growing decreased the enhancement. At longer wavelengths excitation (633 and 785 nm) the enhancement further increased beyond the fourth growth step. This enhancement is caused by the plasmon excitation of narrower gap sizes. The proposed procedure for the SERS substrates is simple, allows covering large surface areas and plasmon band tuning from 530 nm to the near infrared in order to increase overall Raman enhancement.