Thin Metal Films Deposited on Dendrimer Monolayers

Chemical interactions and the evolution of surface morphology resulting from deposition of Cr and Co onto dendrimer monolayers have been investigated by XPS, RAIRS, and AFM. Evidence is presented for formation of metal nitrides and mediation of film morphology as a function of the metal and generation number of the dendrimer comprising the monolayer.     

Composites membranes based on Nafion and PAMAM dendrimers for PEMFC applications

The aim of this work consists in to incorporate organic compounds as PAMAM (Poly-amidoamine) dendrimers into the polymeric Nafion matrix to prepare composite membranes as a possible alternative to reduce methanol crossover effect. Composite Nafion membranes were prepared using a 3 wt% of Generation-4 hydroxyl-terminated PAMAM (G4OH) dendrimers containing 64-terminal OH-functional groups. The influence of PAMAM-(G4OH) dendrimer on chemical–physical properties of the composite membrane was highlighted resulting in a reduction of the methanol permeability (1.05 × 10⁻⁶ cm² s⁻¹) if compared to a recast bare Nafion membrane (8.19 × 10−6 cm² s⁻¹), used as a reference. Good proton conductivity was also observed for PAMAM-(G4OH) composite membrane. The polarization curves carried out at 100 °C in the presence of 2 M methanol have revealed the higher performance of the PAMAM-(G4OH) membrane when compared to a recast Nafion membrane.     

微波法制备3．5GPAMAM树状大分子保护的金纳米粒子

以3．5GPAMAM（3．5代聚酰胺一胺型）树状大分子为保护剂，利用微波法还原HAuCl4溶液制备金纳米粒子．考察了当3．5GPAMAM与HAuCl4物质的量的比一定时，微波照射不同时间对金纳米粒子大小及形状的影响；以及同一照射条件下，3．5GPAMAM与HAuCl4不同的物质的量比值对金纳米粒子大小及形状的影响．利用紫外可见分光光度计、透射电子显微镜对其进行了表征．结果表明，当3．5GPAMAM与HauCl4物质的量的比值一定时，金纳米粒子的形状和大小受微波照射时间长短的影响不大；适当延长照射时间，制得的金纳米粒子的分散性较好．在相同照射条件下，随着3．5GPAMAM与HAu—C14物质的量比值的减小，得到的金纳米粒子粒径逐渐变大，且分散性变差．     

Studies on the complexation between generation‐4.5 methyl ester‐terminated poly(amidoamine) dendrimer and Pd2+ ions in methanol

Poly(amidoamine) (PAMAM) dendrimers have attracted attention because of their well‐defined molecule structures and chemical versatility, which also complicate the mechanism of interactions between metal ions and PAMAM dendrimers. To further understand the complexation of dendrimers with metal ions, the interactions between Pd²⁺ ions and G4.5‐COOCH₃ PAMAM dendrimers were investigated by UV‐vis and FTIR spectrophotometric method. The results show that the addition of K₂PdCl₄ results in covalent attachment of the PdCl alcoholysis product of this complex to tertiary amines within the dendrimers under the appropriate conditions. This process was also supported by X‐ray photoelectron spectroscopy data of the new complex which indicated a 1 : 3 Pd/Cl ratio. The maximum loading of 80 Pd²⁺ ions within the G4.5‐COOCH₃ dendrimers and the best pH value of 8.3 for complexation system are also obtained. Details regarding the Pd species present in solution of different chemical environments are reported. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚酰胺-胺型多聚物作为基因载体的研究现状

近年来,新型非病毒载体在基因治疗中应用广泛,特别是树枝状阳离子多聚物,以其低毒性和特殊的结构特性,成为人们研究的重点。其文对聚酰胺。胺树枝状阳离子多聚物（PAMAM dendrimers）的结构特点、性能、基因转移机制以及近年来在基因治疗中的应用进行论述,并对它作为基因治疗载体的应用前景进行了预测。     

一种稠油原油污水处理破乳剂的合成及性能研究

通过保护与反保护的方法,合成了PAMAM稠油原油污水高效破乳剂。探讨了原油废水的pH值、温度,以及不同PAMAM代数对稠油原油污水破乳效果的影响,结果表明,在温度为20℃,pH值的范围为4.8~10.57的条件下,4代PAMAM树形分子投加20mg/L时,除油率达到96.9%。现场试验表明,PAMAM树形分子是一类性能优良的稠油原油污水破乳剂。     

胺基端基树状分子在铜纳米粒子形成过程中的模板及稳定化作用

通过Micheal加成和胺解的交替反应,制得末端基为氨基的聚酰胺-胺型树状分子（PAMAM）;研究了第7代PAMAM（G7-NH2）在制备铜纳米粒子过程中的模板作用,通过紫外光谱和透射电镜表征了铜粒子的形成过程以及所得铜粒子的大小。结果表明,铜离子不仅与G7-NH2内部叔胺基形成络合物,还与树状分子外部的伯胺基形成络合物;在得到铜粒子的过程中,G7-NH2具有内模板和外模板作用,铜纳米粒子的尺寸随着铜离子与G7-NH2浓度比例的提高而增大;同时,由于铜纳米粒子为G7-NH2模板所包裹,使其在水中具有良好的分散均匀性和稳定性。但在有氧条件下,铜粒子很容易被氧化为G7-NH2（Cu^2＋）n络合离子。     

聚酰胺胺(PAMAM)树状分子在我国的研究进展

综述了聚酰胺胺(PAMAM)树状分子在我国的研究进展;介绍了聚酰胺胺(PAMAM)树状分子的合成方法:发散法、收敛法、发散收敛结合法,以及聚酰胺胺(PAMAM)树状分子在表面活性剂、催化剂、纳米材料、絮凝剂等应用研究领域所取得的成果;并评述了聚酰胺胺(PAMAM)树状分子在我国发展的方向.     

紫外光辐照下以PAMAM树形分子为模板制备Ag纳米簇及光致发光性能研究

以G5．0-OHPAMAM树形分子为模板，用紫外光辐照法制备银纳米簇．用透射电子显微镜、紫外-可见吸收光谱和共振散射光谱等对所制备的银纳米簇进行了表征．结果表明：用紫外光辐照法可以制备尺寸分布均匀、稳定的银纳米簇；且辐照时间、PAMAM树形分子的浓度及Ag^＋／PAMAM树形分子的摩尔比都会对所制备的银纳米簇产生较大的影响．由于所制备的银纳米簇的粒径小于树形分子的流体力学半径，表明树形分子起到了“内模板”作用．同时研究了银纳米簇的尺寸对其光致发光性能的影响，发现通过调节银纳米簇的尺寸可实现其光致发光的可调性．