Lab profile: Stephen Z. D. Cheng, AISMST

Pierre-Gilles de Gennes, the founding father of soft matter and Nobel Prize laureate for physics in 1991, defined soft matter as “all physicochemical systems that have large response functions”. Soft matter encompasses polymers, colloid, gels, granular materials, liquid crystals, liquids, and biological materials that share an important common feature: they can be deformed or altered structurally by a small mechanical stress or perturbation at room temperature. 

Stephen Z. D. Cheng’s early academic training was as a mathematician, then a chemical engineer and a chemist. After receiving an M.S. in polymer engineering from the East China Institute of Textile Science and Engineering (now, Donghua University) in Shanghai, he completed a Ph.D. in polymer chemistry at Rensselaer Polytechnic Institute. Uniting these interests in soft materials research, he joined The University of Akron in 1987 as an assistant professor, where he was subsequently appointed the Frank C. Sullivan Distinguished Research Professor and Robert C. Musson Professor of polymer science and engineering.

Over the course of his career, Cheng has received many awards, including the International Award from the Society of Polymer Science, Japan in 2017 and the Polymer Physics Prize from the American Physical Society in 2013, and has published over 500 articles. He also serves as the Senior Editor of the journal Polymer.

Now he is now taking on a new responsibility as the founding dean and chief scientist of the South China Advanced Institute for Soft Matter Science and Technology (AISMST).

Stephen Z. D. Cheng talked to Materials Today about his research, setting up a new institute, and his future plans...

How long has the Institute been running?

The South China Advanced Institute for Soft Matter Science and Technology (AISMST) was founded at South China University of Technology (SCUT) in May 2016. Our vision is to be recognized as having one of the best academic programs worldwide for our positive impact on humanity through contributions to and leadership in soft matter science and technology. From July this year, I will spend majority of my time in working with AISMST.

How many staff makes up your team? And the new Institute?

As the Chief Scientist of AISMST, I will build up a research group on organic/inorganic hybrid soft matter materials. My research group currently has two associate professors, three postdoctoral fellows, and nine graduate students. I envisage that I will expand my group to three associate professors, five postdoctoral fellows, and about twenty graduate students. At AIMSMT, we already have eleven faculty members, and thirty-one graduate students. Our plan is to appoint around thirty professors and more than one hundred and fifty postdoctoral fellow in the next five to seven years, as well as recruiting more than three hundred graduate students.

What are the major themes of research at AISMST? And in your lab?

AISMST focuses on research and development in various areas of soft matter, conducting both fundamental and applied research. The Institute’s interdisciplinary approach is centered on new molecular designs and syntheses, functional and intelligent materials and manufacturing, as well as practical applications. Overall, AISMST is dedicated to academic discovery, invention and innovation, technology development, as well as the cultivation of talent and world-class education in soft matter.

My recent interests, in particular, are concentrated on the condensed states in polymers, liquid crystals, surfactants and hybrid materials, and the interactions, responses, dynamics, and structures of these materials on varying length, energy and time scales in which the material itself embodies the technology. My activities include investigations of transition thermodynamics and kinetics in metastable states, ordered structures and morphologies, surface and interface structures in electronic and optical materials and advanced functional hybrid materials.

How and why did you come to work in these areas?

I was trained as a mathematician, a chemical engineer, and a chemist. During my graduate studies, I became deeply attracted to polymer science and engineering and entered this research field. Over the past thirty years, I have gradually broadened my research field to encompass soft materials.

What facilities and equipment does your lab have?

We are establishing a comprehensive platform of more than 40 major instruments to meet the high demands of sample preparation, fabrication and processing, and characterization. Advanced setups, such as transmission and scanning electron microscopy, 2D wide-angle X-ray diffractometry and small-angle X-ray and neutron scattering, as well as ultrafast atomic force microscopy and many others, have been established to accomplish delicate tasks with great accuracy. Creativity and efficiency are the two features we would like to emphasize in this area. For instance, we specifically designed our 2D wide-angle X-ray diffractometer to make the most out of the latest rotating-anode X-ray source. In another example, we will employ state-of-the-art technologies, e.g. virtual reality and machine learning, to assist with user training and management of our instruments.

Do you have a favorite piece of kit or equipment?

I always want to explore all the possibilities to find the most appropriate tool or method to the solution of a specific problem, so it is hard to pick a favorite piece of equipment. Nevertheless, since my research has been focused on the structure and phase behavior of soft matter materials, I do have more experience of a few, such as transmission electron microscopy, diffraction and scattering, and thermal analysis, than of others.

What do you think has been your most influential work to date?

I think my most influential work relates to the fundamental understanding of the crystallization, metastability, and phase transformations of polymers. I am also proud of my work inventing and commercially developing polymer optical retardation films for improved viewing angle and color distortion on flat-panel displays. Together with my lab, we have pioneered the design and precise synthesis of nano-molecular hybrid building blocks with controlled compositions, sequences, and topologies for constructing supramolecular entities with predictable structures and functionalities.

What is the key to running a successful lab? And Institute? Do the two require different approaches or emphasis?

The key to running a successful lab is the careful identification of your research direction, the skillful operation of equipment and data analysis, and deep understanding of your area of scientific expertise. Critical to this is the quality of researchers and graduate students working in the lab.

Running a successful lab is different to running a successful institute. For the latter, not only is the excellence of individual faculty members required, but also organized research teams working in different research fields in synergy. Scientific research has developed to such a stage that we need close collaboration between experts in different disciplines, namely we need chemists, physicists, bio-scientists, and engineers, to work together to achieve a common goal.

Just like the past, I work 365 days per year and seven days per week. I have spent most of my time in the lab, rather doing other things that I am interested in, but I am fortunate to have a great team running the corporate administration side of the Institute so that researchers like me can focus on their work.

How do you plan to develop your lab in the future? And what about the Institute?

My role is rather like the captain of a ship. I need to establish a strong leadership team for the Institute with a completely new structure. My strategy is to recognize opportunities and use our diverse skill sets, indigenous or acquired through hiring and collaboration, to lay the fundamental foundations of interdisciplinary soft matter science and technology of tomorrow.

In terms of my own research, I will continue to build up my lab in this new institution and pursue my interests on the precisely controlled structure and functionality of hybrid giant molecules.

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Key publications

1. X. Yu, S. Zhong, X. Li, Y. Tu, S. Yang, R. M. Van Horn, C. Ni, D. J. Pochan, R. P. Quirk, C. Wesdemiotis, W.-B. Zhang, S. Z. D. Cheng. A giant surfactant of polystyrene-(carboxylic acid-functionalized polyhedral oligomeric silsesquioxane) amphiphiles with highly stretched polystyrene tails in micellar assemblies, J. Am. Chem. Soc. 132 (2010) 16741-16744.
2. Y. Li, W.-B. Zhang, I.-F. Hsieh, G. Zhang, Y. Cao, X. Li, C. Wesdemiotis, B. Lotz, H. Xiong, S. Z. D. Cheng. Breaking symmetry towards non-spherical Janus particles based on polyhedral oligomeric silsesquioxanes: Molecular design, “click” synthesis, and hierarchical structure, J. Am. Chem. Soc. 133 (2011) 10712-10715. 
3. X. Yu, W.-B. Zhang, K. Yue, X. Li, H. Liu, Y. Xin, C.-L. Wang, C. Wesdemiotis, S.Z.D. Cheng. Giant molecular shape amphiphiles based on polystyrene–hydrophilic [60]fullerene conjugates: Click synthesis, solution self-assembly, and phase behavior, J. Am. Chem. Soc. 134 (2012) 7780-7787. 
4. X. Yu, K. Yue, I.-F. Hsieh, Y. Li, X.-H. Dong, C. Liu, Y. Xin, H.-F. Wang, A.-C. Shi, G. R. Newkome, R.-M. Ho, E.-Q. Chen, W.-B. Zhang, S. Z. D. Cheng. Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering. Proc. Natl. Acad. Sci. U. S. A. 110 (2013) 10078-10083. 
5. W.-B. Zhang, X. Yu, C.-L. Wang, H.-J. Sun, Y. L. Hsieh, X.-H. Dong, K. Yue, R. M. Van Horn, S. Z. D. Cheng. Molecular nanoparticles are unique elements for macromolecular science: from nanoatoms to giant molecules, Macromolecules 47 (2014) 1221-1239.
6. M. Huang, C.-H. Hsu, J. Wang, S. Mei, X. Dong, Y. Li, M. Li, H. Liu, W. Zhang, T. Aida, W.-B. Zhang, K. Yue, S. Z. D. Cheng. Selective-Assemblies of Giant Tetrahedra via Precisely Controlled Positional Interactions. Science 348 (2015) 424-428.  
7. K. Yue, M. Huang, R. Marson, J. He, J. Huang, Z. Zhou, J. Wang, C. Liu, X. Yan, K. Wu, Z. Guo, H. Liu, W. Zhang, P. Ni, C. Wesdemiotis, W.-B. Zhang, S. C. Glotzer, S. Z. D. Cheng. Geometry Induced Sequence of Nanoscale Frank–Kasper and Quasicrystal Mesophases in Giant Surfactants. Proc. Natl. Acad. Sci. U.S.A. 113 (2016) 14195-14200. 
8. Z. Lin, J. Sun, Y. Zhou, Y. Wang, H. Xu, X. Yang, H. Su, H. Cui, T. Aida, W. Zhang, S. Z. D. Cheng. A Non-Crystallization Approach toward Uniform Thylakoids-Like 2D “Nano-Coins” and their Grana-Like 3D Supra-Structures. J. Am. Chem. Soc. 139 (2017) 5883–5889. 
9. Z. Lin, X. Yang, H. Xu, T. Sakurai, W. Matsuda, S. Seki, Y. Zhou, J. Sun, K.-Y. Wu, X. Yan, R. Zhang, M. Huang, J. Mao, C. Wesdemiotis, T. Aida, W. Zhang, S. Z. D. Cheng. Topologically directed assemblies of semiconducting sphere-rod. J. Am. Chem. Soc., 139 (2017) 18616–18622. 
10. W. Zhang, X. Lu, J. Mao, C.-H. Hsu, G. Mu, M. Huang, Q. Guo, H. Liu, C. Wesdemiotis, T. Li, W.-B. Zhang, Y. Li, S. Z. D. Cheng. Sequence Mandated, Distinct Assembly of Giant Molecules, Angew. Chem. Int. Ed. 56 (2017) 15014-15019.