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Posted by: mus41 on Sep 28, 2016
Yury Gogotsi
Department of Materials Science and Engineering, Drexel University

Wednesday, October 5, 2016 3:35pm - 4:25pm
103 Leonhard Building

Abstract:
Two-dimensional (2D) solids – the thinnest materials available to us – offer unique properties and a potential path to device miniaturization. The most famous example is graphene, which is an atomically thin layer of carbon atoms bonded together in-plane with sp2 bonds. In 2011, an entirely new family of 2D solids – transition metal carbides (Ti2C, Ti3C2, Nb4C3, etc.) and carbonitrides – was discovered by Drexel University scientists [1]. Selective etching of the A-group element from a MAX phase results in formation of 2D Mn+1Xn solids, labeled “MXene”. 17 different carbides and carbonitrides have been reported to date [2-5]. A new sub-family of multi-element ordered MXenes was discovered recently [2]. Structure and properties of numerous MXenes have been predicted by the density functional theory, showing that MXenes can be metallic or semiconducting, depending on their surface termination. Their elastic constants along the basal plane are expected to be higher than that of the binary carbides. Oxygen or OH terminated MXenes, are hydrophilic, but electrically conductive. Hydrazine, urea and other polar organic molecules can intercalate MXenes leading to an increase of their c lattice parameter [3]. When dimethyl sulfoxide or some other polar organic molecules were intercalated into Ti3C2, followed by sonication in water, a stable colloidal solution of single- and few-layer flakes was produced. One of the many potential applications for 2D Ti3C2 is in electrical energy storage devices such as batteries, Li-ion capacitors and supercapacitors [3-5]. Cations ranging from Na+ to Mg2+ and Al3+ intercalate MXenes. Ti3C2 paper electrodes, produced by vacuum assisted filtration of an aqueous dispersion of delaminated Ti3C2, show a higher capacity than graphite anodes and also can be charged/discharged at significantly higher rates. They also demonstrate very high intercalation capacitance (>1000 F/cm3) [4].
1. M. Naguib, et al, Advanced Materials, 23 (37), 4207-4331 (2011)
2. B. Anasori, et al, ACS Nano, 9 (10) 9507–9516 (2015)
3. O. Mashtalir, et al, Nature Communication, 4, 1716 (2013)
4. M M. Ghidiu, Nature, 516, 78–81 (2014)
5. M. Naguib, Y. Gogotsi, Accounts of Chemical Research, 48 (1), 128-135 (2015)

Bio:
Yury Gogotsi is Distinguished University Professor and Trustee Chair of Materials Science and Engineering at Drexel University. He is the founding Director of the A.J. Drexel Nanomaterials Institute and Associate Editor of ACS Nano. He works on nanostructured carbons and two-dimensional carbides for energy related and biomedical applications. His work on selective extraction synthesis of carbon and carbide nanomaterials with tunable structure and porosity had a strong impact on the field of capacitive energy storage. He has co-authored 2 books, more than 400 journal papers and obtained more than 50 patents. He has received numerous national and international awards for his research. He was recognized as Highly Cited Researcher by Thomson-Reuters in 2014 and 2015, and elected a Fellow of AAAS, MRS, ECS, RSC and ACerS and a member of the World Academy of Ceramics.
Posted by: mus41 on Sep 21, 2016
Kathleen J. Stebe
Department of Chemical and Biomolecular Enginering, University of Pennsylvania

Wednesday, September 28, 2016 3:35pm - 4:25pm
103 Leonhard Building


Abstract:
There are important physical fields, intrinsic to soft matter, which we can exploit to direct colloidal assembly. The central idea is this: When a colloid is placed in a soft host, the colloid deforms the host, with some energetic consequence. The host can be a fluid interface, a nematic liquid crystal, or a lipid bilayer membrane. In each of these examples, molding the soft matter host defines energy fields that drive colloidal assembly. In the small deformation limit, important analogies to charge multipoles guide our thinking. The value and limitations of these analogies are explored as strategies are developed for directed assembly.

Bio:
Dr. Kathleen Stebe is Deputy Dean for Research in the School of Engineering and Applied Sciences, University of Pennsylvania, as well as the Richer and Elizabeth Goodwin Professor of Engineering and Applied Science in the Department of Chemical and Biomolecular Engineering, University of Pennsylvania.
Posted by: mus41 on Sep 14, 2016
Huanyu Cheng
Department of Engineering Science and Mechanics, PSU

Wednesday, September 21, 2016 3:35pm - 4:25pm
103 Leonhard Building

Abstract:
Data management represents one of the most important ethical aspects in engineering research. With massive data generated from theoretical, numerical and experimental research, it is crucial to understand the ethical issues behind data management. In this talk, I will first present several ethical issues in engineering research involving data generation, management and use. With a brief introduction on ethical framework for use in discussion, I will then discuss the ethical issues and considerations through one case study, and provide resources to improve ethical awareness.

Bio:
Dr. Huanyu Cheng was appointed an Assistant Professor of ESM and the Dorothy Quiggle Career Development Professor at Penn State in 2015. He earned a Ph.D. and a Master’s degree from Northwestern University in 2015 and 2011 respectively, and a Bachelor’s degree from Tsinghua University (China) in 2010. Throughout Dr. Cheng’s research career, he has worked on structural design and manufacturing of biologically inspired electronics with applications in robotics, biomedicine, and energy. Dr. Cheng has co-authored over 50 peer-reviewed publications, and his work has been recognized through the reception of numerous awards.
Category: ESM News
Posted by: ajm138 on Sep 7, 2016
The Department of Engineering Science and Mechanics at Penn State currently has openings for three new tenure-track Assistant Professors, though exceptional faculty at higher ranks may be considered. ESM’s strategic research areas are aligned with those of the Colleges of Engineering and Medicine, the Materials Research Institute, and the Huck Institutes of the Life Sciences. Applicants are sought with interdisciplinary interests in areas related to computational and experimental mechanics; infrastructure integrity; nano and bionano science and engineering; electronic, optical, and photonic materials and devices; advanced manufacturing techniques; energy harvesting as well as energy-efficient materials and processes (e.g. artificial synthesis); engineered biomimicry; human health and biomedicine; and neural engineering.

Learn more.
Posted by: mus41 on Sep 7, 2016
Michael A. Hickner
Department of Materials Science and Engineering, PSU

Wednesday, September 14, 2016 3:35pm - 4:25pm
103 Leonhard Building

Abstract:

Structured membranes play an important role in improving the flow and resistance characteristics of ion-conducting membranes. Micro-patterned anion exchange membranes have been 3D printed via a photoinitiated free radical polymerization and quaternization process. The photocurable formulation, consisting of diurethane dimethacrylate, poly(ethylene glycol) diacrylate, dipentaerythritol penta-/hexa- acrylate, and 4-vinylbenzyl chloride, was directly cured into patterned films using a custom 3D photolithographic printing process similar to mask projection stereolithography. Measurements of water uptake, permselectivity, and ionic resistance were conducted on the quaternized poly(DU-co-EG-co-VBC) samples to determine their suitability as ion exchange membranes. The water uptake of the materials increased as the ion exchange capacity (IEC) increased due to greater quaternized VBC content. Samples with IECs from 0.98 to 1.63 meq/g were possible with the VBC content ranging from 15 to 25 weight %. The water uptake was sensitive to the amount of PEG in the sample with membranes showing water uptakes from 85 to 410 weight % with PEG fractions from 0 to 60 weight %. The permselectivity of the anion exchange membrane samples decreased from 0.91 (168 weight %, 1.63 meq/g) to 0.85 (410 weight %, 1.63 meq/g) with increasing water uptake and to 0.88 (162 weight %, 0.98 meq/g) with decreasing IEC. These results were relatively consistent with the general view of permselectivity being correlated to the water uptake and ion content of the membranes. Lastly, it was revealed that the ionic resistance of patterned membranes was lower than that of flat membranes at the same material volume. A parallel resistance model was used to explain how the patterning contributed to the overall measured membrane resistance. This model may provide a way to maximize the membrane’s performance by optimal patterning on the surface without chemical modifications of the membrane structure. This seminar will describe our new membrane fabrication procedure in detail and look at other functional materials 3D printing projects in the Hickner Research Group.