最有效的相容剂是两嵌段还是多嵌段聚合物？

采用Monte Carlo模拟方法研究了多嵌段聚合物在A／B／嵌段聚合物三组份体系作为相容剂使用的有效性．占总体积19％的A组份在体系中为分散相．模拟结果显示了两嵌段和多嵌段聚合物在界面上的聚集行为,以及如何影响这个不相容体系的相形为．两嵌段聚合物趋于直立在相界面上,而多嵌段聚合物更容易横跨在相界面上并占据较大的界面积．从而导致多嵌段聚合物更有效的阻止体系相分离的发生．     

Capability of DNA-fueled molecular machine in tuning association rate of DNA-functionalized gold nanoparticles

The capability of our newly developed DNA-machine-driven strategy in tuning the association rate of DNA-AuNPs was compared with that of linker-addition strategy which has potential practical applications in different fields. The new established strategy shows its superiority to the linker-addition strategy in tuning the association rate of DNA-AuNPs in both pre-incubation treatment and non-incubation treatment conditions since its two components (a complex and a catalyst-oligonucleotide) can be individually optimized to make the machine run at an optimal rate. This strategy will provide a more convenient and flexible option in designing an oligonucleotide detection system and building a complex and versatile device.     

光散射法研究丙烯酸十八酯和苯乙烯微乳液 共聚机理

在十六烷基溴化吡啶/叔丁醇/15%丙烯酸十八酯和苯乙烯/水体系的O/W微乳液中,使用动态光散射法,研究其中两种单体共聚反应的成核机理。结果表明,聚合过程中乳胶粒成核位置主要在增溶胶囊的单体微珠中,乳胶粒主要依靠单体微珠不断提供单体而长大。     

Influence of Monomer Types on the Designability of a Protein—Model Chain

In a three-dimensional off-lattice model,the method of Shakhnovich and Gutin for minimizing the Hamiltonian is applied to the design of a protein-model chain.The effect of the number of hydrophobic and hydrophilic monomer types on the designability of a protein-model chain is investigated.The simulation results reveal that the number of hydrophobic monomer types is a much more important factor than that of the polar monomer types in the design of a protein-model chain.     

Theoretical Study on Reaction Mechanism of Aluminum-Water System

在B3LYP/6-311+G(d,p)和QCISD(T)/6-311++G(d,p) 水平上,对气相中铝与水的反应进行了计算. 理论计算结果表明,铝水反应经过了三条可能的反应通道并且涉及了四个异构体、七个过渡态和两种产物. 其中两条反应通道所涉及的中间物和产物已被实验测得. 同时,在298 K和2000 K计算了铝水反应的焓变和吉布斯自由能,一些计算结果与以前的计算和实验结果吻合较好.     

Theoretical Study of Haloacetonitrile Anions: CH2XCN- (X=F, Cl)

使用HF-SCF、Becke3-LYP和MP2理论方法和Dunnning基组aug-cc-PVTZ对卤代乙腈负离子CH2XCN-(X=F,Cl)进行一系列计算. 计算说明电子垂直贴附到中性分子是吸热反应. 构型优化的负离子CH2FCN-主要是价层束缚类型,CH2FCN-→CH2CN+F-是非绝热解离过程. 在描述负离子的电子结构以及解离贴附动力学时, 理论计算与实验结果比较得出Becke3-LYP方法是合理的,然而在CH2ClCN-→CH2CN+Cl-的解离势能曲线的计算中,MP2和Becke3-LYP方法有显著的不同.     

Internal Conversion Process of Chlorophyll a in Solvents in Femtosecond Pump-Probe Laser Fields

采用约化密度矩阵理论研究了溶液中叶绿素a分子的内转换过程. 内转换时间可以通过模拟实验荧光亏蚀光谱得到. 计算得到的叶绿素a分子在乙酸乙酯、四氢呋喃和二甲基甲酰胺溶剂中的内转换时间分别是141、147和241 fs. 理论分析表明：荧光亏蚀光谱曲线的振荡行为主要是由分子布居在耦合势能面间的振荡引起的. 分析了两个电子态之间非绝热耦合对内转换时间及荧光亏蚀光谱的影响,还讨论了叶绿素a分子与溶液耦合作用对内转换时间的影响.     

石英晶体微天平用于微囊藻毒素在聚合物涂覆的金片表面吸附

合成了具有不同功能化的聚苯乙烯树脂,利用石英晶体微天平对树脂和微囊藻毒素相互吸附作用进行实时监测和研究．研究发现,吸附的pH和表面性质对于吸附量有重要的影响,而温度影响不大,中性pH氨基树脂对微囊藻毒素的吸附效果最好.     

Surface-field-induced effects on morphologies of lamella-forming diblock copolymers in nanorod arrays

The surface-induced effect on the morphologies of lamella-forming diblock copolymers in nanorod arrays is studied by using the self-consistent field theory.In the simulation study,a rich variety of novel morphologies are observed by variations in the strength of the surface field for the diblock copolymers.Different surface-field-induced effects are examined for the diblock copolymers in the arrays with distinct preferential surfaces.It is observed that the majority-block preferential surfaces have more obvious induced effects than those of minority-block preferential surfaces.The strong surface fields exhibit different behaviours from those observed in the weak surface fields,by which the morphologies possess cylindrical symmetries.Results from this research deepen the knowledge of surface-induced effects in a confinement system,which may aid the fabrication of polymer-based nanomaterials.     

聚甲基丙烯酸甲酯与苯乙烯-丙烯腈共聚物混合体系相分离初期的固体NMR研究

本文用氢谱宽线固体NMR技术研究了聚甲基丙烯酸甲酯(PMMA)和苯乙烯-丙烯腈共聚物(SAN)混合体系不稳相分离初期阶段, 得到了在分相过程中弛豫谱的变化规律, 测定了相分离增长速率。结果指出: 随着退火时间的增加, 两相体系形成; 大分子扩散方式是由浓度低的区域向浓度高的区域扩散, 扩散系数为负值; 相分离增长速率的数量级与用光散射研究的结果相同; 分子相互作用的相关距离为46.5 nm。