1.报告时间:9月5日(周六)下午15:00
报告地点:科技创新大楼C501室
报告题目:Nanocomposites of polymers and carbon-based nanofillers: improving mechanical properties through modular, flaw- tolerant fabrication
Abstract:
Nanocomposites of polymers and carbon-based nanofillers: improving mechanical properties through modular, flaw-tolerant fabrication
SonBinh T. Nguyen
Dept. of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208-3113
Synthetic nanostructures such as carbon nanotubes and graphene oxide have stiffness, strength, and toughness that exceed those of any commercial structural material (e.g., steel, concrete, polymers) by several orders of magnitude. However, their applications have been limited, as currently available techniques for assembling these nanoscopic building blocks into macroscopic nanocomposite materials fail to extend their impressive nanoscale properties to the macroscale. In contrast, nanostructures of brittle minerals such as CaCO3 can be assembled into strong macroscopic natural materials like nacre or bone in the presence of a small amount of proteins. Nature achieves this through a synergistic combination of atomic-scale control of chemical interactions and nanometer- to micrometer-scale control of component organization. Taking inspirations from these natural examples, we have been able to design lightweight, mechanically strong nanocomposites, either by mechanical fabrication and chemical crosslinking, or by interfacing nanofillers such as carbon nanotubes and graphene oxide sheets with polymers.
Nevertheless, the mechanical properties of the aforementioned composites are still limited by many types of flaws and relatively weak interfaces, preventing them from achieving high macroscopic strengths comparable to their parent nanostructures. As such, we have also focused our efforts to fabricate nanocomposites that are flaw-tolerant, rather than flawless. This talk will chronicle our findings over the last five years in the fabrication of composite films of polymers and carbon-based nanofillers and our attempts to improve their mechanical properties through structure-property studies.
2. 报告时间:9月6日(周日)下午14:00
报告地点:科技创新大楼报告厅
报告题目:
a. From single-site catalysts and supramolecular assemblies to metal-organic frameworks (MOFs) and porous organic polymer (POPs): Bridging homogeneous and heterogeneous catalysis
b. Publishing a high-impact, scholarly scientific paper: a short, informal process tutorial for beginning students
Abstract:
From single-site catalysts and supramolecular assemblies to metal-organic frameworks (MOFs) and porous organic polymer (POPs): Bridging homogeneous and heterogeneous catalysis
SonBinh T. Nguyena,b
aDepartment of Chemistry and the Center for Catalysis and Surface Science, Northwestern University, Evanston, IL, 60208, United States of America. bArgonne National Laboratory, Argonne, IL, 60439, United States of America
This presentation will discuss the efforts by our research groups at Northwestern University and Argonne National Laboratory in trying to bridge homogeneous and heterogeneous catalysis through the use of supramolecular environments and porous materials, such as metal-organic frameworks (MOFs) and porous organic polymer (POPs), as platforms for deploying homogeneous catalysts.
Supramolecular assemblies are large soluble structures constructed from molecules rather than atoms as building blocks. As thermodynamically stable structures, the stability of these materials comes from marshalling multiple weak interactions in a highly reinforcing way. In this sense, supramolecular chemistry has the potential for bringing together cooperative catalytic sites, stabilizing potent reaction centers, and creating architectures that elicit reaction selectivity. Previous examples from our group include assemblies capable of catalyzing enantioselective oxidation reactions, enantioselective epoxide ring-opening, and acyl transfer reactions with applications in sensing.
As hybrid materials derived from well-defined molecular building blocks, newly emerged porous materials such as metal-organic frameworks (MOFs) and porous organic polymers (POPs) are natural solid-state 3-D versions of supramolecules. These materials have many of the desirable features of zeolites, such as high surface area and porosity, and can be similarly effective in size- and shape-selective catalysis. However, given the enormous diversity of potential structures and chemical functional groups that can be incorporated into the pores of MOFs and POPs, these porous materials have the potential to extend catalysis far beyond the realm of zeolitic chemistry to include enzyme-like behaviors such as adapted flexibility during catalysis, substrate pre-concentration effects, active-site isolation and protection, and tunable hydrophobicity. Most importantly, recent developments in MOF and POP synthesis have given rise to catalytically active materials with unprecedented stability and novel activity that were not observed in solution.
Publishing a high-impact, scholarly scientific paper: a short, informal process tutorial for beginning students
SonBinh T. Nguyen
Dept. of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208-3113
In the modern world, where there is a plethora of new journals appearing every month and almost any manuscript can be published somewhere, the task of publishing a high-impact, scholarly scientific paper seems to be more difficult than ever for students who just begin their scientific careers. Even for those that are native English speakers, this task is not something that they were prepared for during high school and college. The first reason for this difficulty is the increased complexity in the structure of the paper themselves. While the scientific articles of the past tend to be terse and full of factual results without much interpretation and speculations, the modern manuscripts are a lot longer and must include a discussion section to explain all of the results for the general audience. In addition, the introduction and conclusion statements have also been lengthened to several paragraphs to give a proper background to the work, to address the modern criteria for broad impact, general interest, and novelty, and to speculate about the future impact of the work. Even when this formulaic template is followed rigorously, it is not a guarantee that the resulting manuscript can eventually be published in a high-impact, scholarly journal.
The increased complexity in the research process also hinders the lofty goal of high-impact, scholarly publishing. In an age where technology is moving ahead at a breathtaking pace and interdisciplinary is the buzz word, the perception is that it is not enough for a young science student just to go into the laboratory, do the research, produce results, and write them up. He/she also has to “choose” the “right” interdisciplinary research topic, do the “right” experiments with the “right” collaborators, and spend a lot of time preparing a manuscript that is in a “publishable” form. This includes adhering to complex journal templates, preparing beautiful figures, and writing discussion and impact statements that will hopefully generate positive responses from both the peer-reviewer and reader communities. The whole process requires a tremendous amount of coordination and the average high-school and college educations do not adequately prepare the student to face it during graduate school. He/she has to rely on his/her adviser for advices on how to tell a good story, maintain a high level of scholarship, and do not oversell the impact of the results. Yet the adviser is busier than ever and can hardly afford the time to give individual students the proper training on all the steps that will make the manuscript as perfect as it can be before submission. Coupling to that deficiency is an overworked, time-crunched peer-review community who becomes increasingly impatient with manuscripts that do not come to the punch line in a succinct manner. The end results are higher rejection rates and frustrations by everyone involved. However, with some planning and hard work, the good young scientist can overcome all of these and make publication a much more pleasant process.
This presentation aims to introduce the modern science student through the process of getting a high-impact, scholarly scientific paper published using examples from the presenter’s own scientific careers. By showcasing both good and bad situations in his publishing experience, the presenter hopes to partially remedy the challenges described above, encourage young science students to become better communicators, and reduce both the amount of work to publish and the level of frustrations in the growing global scientific community. Readers who are interested in learning more about the writing/publishing process for international journals in the chemical sciences can consult the excellent articles by Roald Hoffman, George Whitesides, and the editors of ACS Nano, Chemistry of Materials, the Journal of Physical Chemistry family of journals, ACS Catalysis, and Carbon. As one can see from these references, there are plenty of helpful guidance for the whole scholarly publishing process and the beginning scientist is nor really alone.
Brief Biography:
SonBinh T. Nguyen received a doctoral degree in Chemistry under the directions of Profs. Robert Grubbs and Nathan Lewis at Caltech, where he was an NSF and an NDSEG predoctoral fellow. After an NSF postdoctoral fellowship with Prof. K. Barry Sharpless at Scripps, SonBinh began his independent career at Northwestern in 1996, where he is now a Professor of Chemistry. He is also a Senior Fellow in the technical staff at Argonne National Laboratory. At Northwestern, he has held the Dow Research Professorship, the highly prestigious McCormick Professorship of Teaching Excellence and the Directorship of the Integrated Science Program.
SonBinh has coauthored over 250 manuscripts, held over 30 patents, and is the recipient of many awards. His expertise is in the broad areas of chemical synthesis, catalysis, soft material synthesis, and biologically inspired materials chemistry. In 2014, he was named a Highly Cited Researcher by Thompson-Reuters.