④ Advanced Light Scattering Techniques and their Applications

主 讲 人：Dr. Coline Bretz  LS Instruments, Fribourg, Switzerland

Dr. Coline Bretz is an expert in advanced light scattering technologies. She studied colloidal science at the Paris 7

University (France) as well as the University of Pennsylvania (USA) and holds a PhD in physical chemistry. She joined

LS Instruments as a product scientist in 2017 and now leads the Sales & Marketing business unit. She was the winner of

the 2019 MDPI-Polymers Prize awarded by ECIS, the European Colloid and Interface Society.

 

Light scattering is a powerful characterization technique routinely used in research and formulation development in diverse area such as life sciences, food, personal care products or advanced materials. Depending on the specific technique employed, it provides a measure of the size (DLS) or shape (SLS) or determines the viscoelasticity of a sample (DWS).  While these are well-established characterization techniques, several significant improvements have gained traction over the past decade. This presentation will feature a short review of novel techniques enabling a wider range of applications, such as Depolarized DLS, Non-Ergodic DLS, Modulated 3D DLS or Echo-DWS. 

⑤ Characterization of Soft Materials by 3D Cross Correlation Light Scattering and Diffusing Wave Spectroscopy

主 讲 人：Prof. Dr. Frank Scheffold  Physics Department and Fribourg Center for Nanomaterials, University of Fribourg

Frank Scheffold, born in 1969, holds a chair in experimental physics at the University of Fribourg (Switzerland). He

studied at the University of Konstanz (Germany) and the Weizmann Institute of Science (Israel, with Prof. Jacob Klein).

He received his Ph.D. from the University of Konstanz in 1998 for research he had carried out at the Institut Charles

Sadron (Strasbourg, France) and in Konstanz with Prof. Georg Maret. After his habilitation at the University of Fribourg in the group of Prof. Peter Schurtenberger, he was appointed associate professor in 2004. Since 2009 he has held the chair of "Soft Matter and Photonics." Since 1996 he has authored about 120 peer-reviewed scientific articles.  He was a visiting scholar for several months at UC Los Angeles (2009), the University of Queensland (2014), and New York University (2019).  His research interests include the optics of complex systems, static and dynamic light scattering, diffuse light propagation, the dynamics of colloidal systems, aggregation and phase behavior, and the fabrication and characterization of soft materials. From 2011-2019 he served as a member of the Swiss National Research Council. He is co-founder and currently chairman of LS Instruments AG, Fribourg. He was a founding member of the Swiss National Centre of Competence in Research "Bioinspired Materials" based in Fribourg and was a member of the Centre's Executive Board from 2014 to 2022.

 

Information on mesoscopic length scales is required to characterize the structural and dynamic properties of soft materials, polymers, liquid crystals, small particles and droplets. Static and dynamic light scattering (SLS/DLS) experiments in the single scattering regime can provide such information . In many systems, however, these powerful techniques or affected or fail due to multiple scattering of light. Here I will discuss several experimental innovations that have emerged over the last two decades to overcome such limitations. New concepts and technological advances have led to a more widespread application of methods such as 3D static and dynamic light scattering (3D LS) as well as diffusing wave spectroscopy (DWS). To illustrate their use and range of applications, I will discuss some examples taken from our research and of others. The examples I will discuss are the study of thermosensitive microgel particles, strongly interacting charged colloids and emulsions , and the microrheology of protein and polyelectrolyte solutions.

③ Applications of Diffusing-wave Spectroscopy in Food

主 讲 人：潘伟春教授  浙江工商大学

潘伟春教授在休斯顿大学获得化学工程博士学位，师从Peter Vekilov教授，其论文主旨为蛋白质分子之间的相

互作用及其在蛋白质相变中的应用，他是两步机制的贡献者之一。之后他去了日本东北大学，与Tsukamoto

Katsou教授一起工作，聚焦微重力条件对蛋白质晶体成核和生长的影响。他在2011年加入浙江工商大学食品科

学与生物技术学院。他试图建立食物蛋白质和其他生物大分子之间分子间相互作用的关系图，揭示了肌肉蛋白的盐析机制，并在食物中发现了纳米蛋白质颗粒，这种结构可用于判断食品质量并指导食品工艺的发展。

 

The complexity of food, high heterogeneity with hierarchical structure, non-equilibrium with unceasing spatiotemporal changes of its compositions, and intrinsically complex interactions, hampers its study. On the other hand, the tremendous impact of food on human being health encourages this kind of research. Long time practice suggests that micro-structure of food is a promising candidate to mitigate this dilemma. However, how long time and how big area to capture this food structure is highly uncertain. In addition, what is the technique suitable to fulfill this job? Researches in soft materials suggest that Diffusing-wave Spectroscopy is an ideal one. In this presentation, several samples in food research have been given I hope that all these cases could shed light on the applications of this innovative technique in food. 
 

② 带电大分子在受限环境下的非扩散型拓扑动力学

主 讲 人：贾迪 研究员  中科院化学研究所高分子物理与化学国家重点实验室

贾迪研究员2021年加入中科院化学所。2021年获得“国家海外优秀青年科学基金”资助、“中科院百人计划”

资助。2019 年荣获 Journal of Chemical Physics期刊“年度最佳审稿人”称号。具有散射技术与高分子物理的专

业特长，主要研究方向为多尺度自组装带电软物质----从基础研究到创新应用。具体包括带电高分子与带电

软物质体系的动力学、结构、相行为、反应动力学等，并将基础研究上取得的成果应用到生物医疗工程、能源、环境等领域中，力争以基础研究创新带动应用创新。

 

过去70多年以来人们认为高分子链在受限环境下总是可以自由扩散运动的，并且遵从爱因斯坦扩散方程。高分子链在不同的受限环境下有不同的运动模型。即使是在最强烈的受限环境下，高分子链的运动符合由P. G. de Gennes和S. F. Edwards提出的著名的管道模型 （reptation），在此模型中，高分子链仍然可以像蛇一样向前爬行，符合一维无规自由扩散运动（one-dimensional random walk），因此，无论是在弱受限环境还是强受限环境中，高分子链都是可以自由运动的，并且遵从爱因斯坦扩散方程。本报告将介绍一种新型动力学，即“非扩散型拓扑动力学（Non-diffusive Topologically Frustrated Dynamics）”。在此受限环境中高分子整链是不能自由扩散运动的，但是一条链内的局部链段可以在每个凝胶网格内做多级局部松弛运动，其本质是多熵位垒造成的一种能长存的亚稳态。本报告会详细阐明为什么在更强的受限环境下（reptation管道模型）高分子链能够进行一维自由扩散运动，而在较弱的拓扑受限环境下，高分子链反而不能进行自由扩散运动，并深入对比了我们这一新发现与著名的管道模型的区别。利用这一新型动力学可以在室温下把DNA链“困”在高含水量的水凝胶中，且DNA等生物大分子仍可保持其生物功能性。因此，这一新型动力学对基因工程，药物释放等领域具有重大价值。

① 动态光散射的基本原理与数据解析
主 讲 人：李牧 助理研究员  深圳综合粒子设施研究院
李牧，2022年博士毕业于华南理工大学，获理学博士学位，现在深圳综合粒子设施研究院参与同步辐射光源的

相关工作。他的主要研究方向为小角散射与动态光散射理论、方法学与软件开发，及其在物质表征中的应用。

已发表SCI论文6篇，并开发了小角散射与动态光散射数据分析软件，获得软件著作权一项。

动态光散射是一种利用溶液中粒子布朗运动对光的准弹性散射来对粒子进行表征的方法。动态光散射可以对溶液中的粒子进行原位测试，可获得有关扩散系数、粒径以及粒径分布等丰富信息，在化学、生物、材料等领域应用广泛。然而动态光散射原理较为复杂，并且由于病态问题的特性，其数据解析具有一定的主观性与不确定性。因此，本报告将从基础的动态光散射理论出发，对动态光散射的原理与常用数据解析方法进行介绍。并介绍新发展的基于机器学习框架的多角度动态光散射数据联合分析方法。