系列讲座—2016 International Summer School on Frontiers of Physics系列讲座

发布时间:2016-06-16浏览次数:516

题: Unravelling New Phenomena in Polymer Science at Both the Ensemble and Single-molecule levels

报告人:毕务国  博士

 

间:2016620 上午9

点: 理学楼212会议室

 

报告人简介

   2014.2 – 今,新加坡国立大学,物理系博士后。

研究领域:利用单分子力研究双链 DNAs 之间的相互作用以及对 DNA 序列的依赖关系;

2012.12 – 2013.12,美国芝加哥大学化学系博士后。

研究领域:分子电子学。利用单分子破结技术研究单个分子的电学性能;

2011.9 – 2012.11新加坡南洋理工大学数理学院化学与生物化学系博士后,。

研究领域:利用单分子荧光追踪技术研究凝胶粒子结晶动力学以及细菌集群运动动力学;

2012.4在新加坡南洋理工大学数理学院化学与生物化学系获得博士学位,

研究领域:利用单分子荧光追踪技术研究高分子薄膜结晶动力学,高分子薄膜中相分离以及咖啡圈形成的动力学。

代表性论文:

1. Wai-Yip Lo, Wuguo Bi, In Hwan Jung, Luping Yu*, Nano Lett. 15 (2), 958 2015 (IF = 13.592)

2. Shengtao Lu, Wuguo Bi, Fang Liu, Xiangyang Wu, Bengan Xing and Edwin K. L. Yeow*. Phys. Rev. Lett. 111, 208101 (2013). (IF = 7.512)

3. Wuguo Bi, Xiangyang Wu and Edwin K. L. Yeow*. Langmuir 28, 11056 (2012). (IF = 4.457)

4. Wuguo Bi, Edwin K. L. Yeow*. Phys. Rev. Lett. 106, 078001 (2011). (IF = 7.512)

5. Wuguo Bi, Jefri S. Teguh, Edwin K. L. Yeow*. Phys. Rev. Lett. 102, 048302 (2009). (IF = 7.512)

 

报告内容简介:

Single-(macro) molecule tracking is used for the first time here to study the crystallization process in ultrathin layers of single poly(ethylene oxide) (PEO) chains. Diffusion trajectories of macromolecules diffusing toward the crystal followed by deposition onto the crystal-growth front display different types of motion, such as Brownian and directed motions, prior to crystallization. We show that PEO chains in the amorphous layer and in the less concentrated or depleted zone exhibit Brownian motion of different diffusion rates as a result of heterogeneities in the environment. The phase evolution of thin polymer blend film of polystyrene (PS) and poly(2-vinyl pyridine) (P2VP) triggered by solvent annealing is examined at both the bulk and single-(macro)molecule levels using wide-field microscopy (WFM). The transitions between different evolutionary stages in the nucleation and growth process are clearly visualized in real-time and without intermittent breaks. The nucleation of PS holes arises from the coalescence and growth of P2VP domains and the holes expand in a complex manner involving the dewetting of PS and the absorption of P2VP domains into the holes. The formation of multiring deposits of poly(2-vinyl pyridine) P2VP from the evaporation of a P2VP-(2,6-lutidine + water) drop on a glass substrate does not conform to the conventional pinning-depinning mechanism. Instead, ring-like deposits are formed when the droplet undergoes several cycles of spreading and receding where for each spreading event, a P2VP ridge is formed at the contact line when the polymer flows toward the outward advancing edge. A surface tension gradient created as a result of the solutal-Marangoni effect plays an important role in enhancing the droplet spreading rate.

 

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