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Recap for 88th ACS Colloid & Surface Science Symposium

88th ACS CSS UPenn 2014

Overview

The 88th American Chemical Society Colloid & Surface Science Symposium was held at University of Pennsylvania from June 22 through 25. This year, the symposium was co-chaired by three distinguished scientists from UPenn, John Crocker (Professor of Chemical and Biomolecular Engineering), Kathleen Stebe (Richer & Elizabeth Goodwin Professor of Chemical and Biomolecular Engineering, Deputy Dean for Research, School of Engineering and Applied Science), and Arjun Yodh (James M. Skinner Professor of Science, Department of Physics and Astronomy, and Director of The Laboratory for Research on the Structure of Matter). This symposium presented 2 plenaries, 47 keynote and invited talks, and more than 600 talks and posters given by researchers from 28 countries. In this short article, I will briefly summarize a few talks that are relevant to my field.

Interesting Talks

Zachary Farrell from David Green Group at University of Virginia presented aggregative growth model for silver nanoparticles in ethanol without using reverse micelles as phase transfer agents. They started from traditional calculations for several interactions in the system, such as Van der Waals force, electrostatic force, and steric interaction. Transmission electron microscope (TEM) images of the final products confirmed that greater ionic strength and higher steric effect help to form homogeneous particles. It would be interesting to compare the difference with my own silver system and look into underlying chemical mechanisms.

Dr. Zhihai Li (Research Assistant Professor in Eric Borguet Group) at Temple University showed his work on single molecule conductance of molecules by using Scanning Tunneling Microscopy (STM) break junction technique. They investigated junction resistance of different molecules including linear alkanethiols which are also used as particle protective ligands in our group. A very interesting application of this technique is single-molecule sensing of acidity, since the current changes as the conformation of the molecular wire changes in different environments.

Michael Salerno from Gary Grest Group at Sandia National Lab talked about simulation of mechanical properties of gold nanoparticle membranes covered by alkanethiols. The calculation was based on another work which reported self-assembled monolayers from 5-nm gold nanoparticles. They revealed that carboxyl groups are slower to assemble than methyl groups, and that longer carbon chains pack stronger than shorter ones. These findings, if match with real experimental results, would be useful for us and any groups who need to design assembled structures from metal nanoparticles.

Besides the talks above, Yijing Liu from Zhihong Nie Group at University of Maryland, College Park presented excellent work on self-assembly of molecular and nanoparticle amphiphiles with controlled patterns. Qingjie Luo from So-Jung Park Group at UPenn showed how to control the location of 2.5-nm gold nanoparticles in polymer assemblies. Grazia Gonella from Hai-Lung Dai Group at Temple characterized large silver nanoparticles by second harmonic light scattering.

Two of my lab mates Dejun Chen and Yanyan Wang gave oral presentations on “Organic-Stabilizer-Free Synthesis of Shape-Controlled Platinum Nanocrystals by Interfacial Galvanic Exchange Reactions”, and “Activity Enhancement of Oxygen Reduction Reaction by Sub-monolayer Sulfide Adsorption on Pt Nanoparticles”, respectively.

My Work

I gave a talk entitled “Controlling Size and Homogeneity of Thiolate-protected Sub-5nm Silver Nanoparticles by Modified Digestive Ripening Process”. Controlling size and homogeneity of metal nanoparticles is one of the most important prerequisites for their potential applications. Among many methods, digestive ripening is an effective process to prepare monodispersed NPs from polydispersed ones. Gold is widely studied while silver is still relatively less explored due to its instability. In this presentation, we report our recent progress on the fine control of thiolate-protected silver nanoparticles below 5 nm. The results in this work contribute to the progress of the synthesis and thus application of monolayer-protected silver nanoparticles. I was so lucky as to have Dr. Stebe sitting among the audience. After the talk, she asked one question and said that she used to work on a similar topic years back. She was kind enough to give me some references. This was very helpful for my research.

Yangwei Liu 88th ACS CSS UPenn 2014

For more exciting projects that are currently going on in my group, please visit YuYe J. Tong Group’s webpage. If you are interested in collaboration, co-funding application or other scientific activities and need me to bridge over, feel free to contact me and I am more than happy to help.

Website for 88th ACS Colloid & Surface Science Symposium:
http://www.colloids2014.lrsm.upenn.edu/

Related articles:
2014 DOE Annual Merit Review Meeting (Fuel Cell Topics Recap) 
Highlights of 58th EIPBN Conference 
A Brief Note for ISMPC13 
2013 DOE Catalysis Working Group Meeting 

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Thoughts on Proposal Peer Reviewing System

Peer review

On Feb 7, an article entitled “Peering Into Peer Review” by Jeffrey Mervis was published on Science. (Vol. 343 no. 6171 pp. 596-598) This article discussed the current status of proposal peer reviewing system. According to the statistics from the tracking study for the funded proposals, the initially highly rated projects have not obtained significantly higher achievements than those didn’t get a good score at the beginning of the funding.

I have never reviewed for a research proposal. But my reviewing experience for a broad range of journal articles tells me that there is no easy way to judge a work’s importance using a fit-for-all criterion. Although this phenomenon can be explained from different points of view, there are four issues that need to be considered before making conclusions about the fairness of the funding peer-review system.

First, scientific research has its own cycle, which may vary depending on the topic of the study. Even for the same topic, one cannot predict when a promising result can be obtained. Science is largely unpredictable. Good ideas may be proven wrong at times.

Second, it is very likely that a proposed research got a low score during the peer-review process merely because it is an “outdated” or “old-fashioned” topic, which makes the reviewers thought that it has a lower impact than those popular ones. However, those not-so-hot research areas have no reason to publish less influential papers in terms of scientific contribution.

Third, the proposals that successfully stood out with high scores could be very impactful themselves. However, the measuring standards – the number, time, and impact of the publications, are not necessary to reflect the true value of that specific research project.

Last but not least, writing a good proposal is only the very first step of carrying out good science. A highly ranked proposal needs fulfillment – a continuous efforts made by researchers, post-docs, and students. Besides, with the progress of the project, the PIs need to timely adjust the direction according to the updated situation. All of the above factors are not able to be evaluated during the peer-reviewing process.

Anyhow, there’s nothing to blame the peer-reviewing system. Perfect systems do not exist. The current process may be the best we can do so far to evaluate proposals. Scientists themselves are the ones who know better than anyone else whether a project is important enough to be granted or not. So, let us give science a little time and patience to prove itself by the outcomes.

2014 DOE Annual Merit Review Meeting (Fuel Cell Topics Recap)

U.S. Department of Energy Annual Merit Review and Peer Evaluation Meeting (DOE AMR Meeting) was held in Washington, DC June 16-20, 2014. Sponsored by DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office, the AMR Meeting is an annual event for exchanging ideas, reporting developments, and establishing collaborations among governmental offices, national labs, industry, and academia.

2014 AMR banner2014 DOE Annual Merit Review Meeting

Overview

From 2004-2013, DOE granted $2.5 billion for hydrogen and fuel cell research and development. The funding in the past fiscal year is $145 million. The investment led to hundreds of patents and some of them have turned to commercial technologies. As raised every year, cost, durability, and performance are the main issues to be solved. The performance of catalysts goes down after multiple cycles. The efficiency is only 27% for current fuel cells. The cost of energy is $55/kw. Although the price has been reduced by 30% since 2008 and 50% since 2006, it is still challenging to reach the goal of $40/kw by 2020, and $30/kw ultimately. (source: DOE Hydrogen and Fuel Cells Program record)

Fuel cell catalysts

Catalysts are the essential part of fuel cells. The general goals in this research include improving the activity, reducing the use of Platinum Group Metals (PGM, thus reducing the price) by incorporating non-PGM in alloys or core-shell structures, and increasing the stability of catalysts in terms of poisoning, running cycles, and voltage.

Dr. Dennis van der Vliet (3M) reported their achievements in making durable catalysts for fuel cell protection during transient conditions. Dr. Radoslav Adzic (Brookhaven National Laboratory) showed their work on synthesizing high performance and stable Pt monolayer on inexpensive nanostructures as oxygen reduction reaction (ORR) catalysts. This research is partly relevant to a project I am working on which deals with shape-controlled gold nanocrystals covered with platinum shell. Dr. Sanjeev Mukerjee (Northeastern University) applied various approaches to synthesize iron-based catalysts for Proton Exchange Membrane Fuel Cells (PEMFCs). Dr. Anusorn Kongkanand (General Motors) investigated Pt-Ni dealloyed catalysts which show high activity. Dr. Branko Popov (University of South Carolina) studied ultra-low doped Pt/activated carbon composite catalysts for PEMFCs.

Other relevant interesting work

Dr. Piotr Zelenay (Los Alamos National Laboratory) talked about their progress in developing portable methanol fuel cells. In terms of materials, they used PtRu nanotubes, PtRuCu nanowires, and PtRuPd catalysts. They also looked into supporting materials and other aspects. These fuel cells can tolerate long running time with optimized conditions.

For studies on electric vehicles, a cool research is wireless charging which may free the cars from physically connecting to the station. Dr. P.T. Jones (Oak Ridge National Laboratory) reported that they can achieve 85% efficiency at 6.6kW wireless charging. They will test Toyota electric cars soon. A similar work led by Dr. Allan Lewis (Hyundai) is also underway. Both of them claimed that the charging process is harmless to human body or to electronic device at a safe distance.

How far are we from driving fuel cell cars?

Fuel cell cars for daily use have been introduced and advertised by car makers such as Toyota and Honda. There are also ongoing projects funded by DOE focusing on developing fuel cell trucks and airport supporting buses.

However, one big concern for potential customers is the safety of carrying hydrogen and oxygen tanks on a car. If not well designed, they can be turned into bombs. It is good to know that serious studies have been performed in several institutions. Dr. Eric Brosha (Los Alamos National Laboratory) reported their progress in developing hydrogen sensors. They tested various conditions such as high temperature, wind, vibration, and even effect of spiders. Those sensors can be used for stationary and infrastructure applications, and are extendable to vehicle protection. Dr. Nick Barilo (Pacific Northwest National Laboratory) presented the efforts from Hydrogen Safety Panel, and showed their mobile app which is a fast safety information resource. The app aims at combining all the safety information in one place for people to check and learn. Besides that, their knowledge websites H2incidents.org and h2bestpractices.org have accumulated increasing number of visitors and making broad impacts over years.

Another issue that may be an obstacle for the acceptance of fuel cell cars is how easy can a hydrogen fueling station be accessed. The cost of building a fueling station is several times more expensive than building a conventional gas station. However, those stations have to be ready for use before fuel cell cars go to the market. It is an investment that no one can guarantee the return. At present, the government and a handful of car makers are sharing the risk by building fueling stations starting from California. Moreover, DOE has supported a project called Hydrogen Fueling Infrastructure Research and Station Technology (H2FIRST) to reduce the cost and time of building the fueling stations, and to improve the reliability of the construction (Fuel Cells Bulletin, 2014, 5, 7–8). If everything goes smoothly, hopefully we may expect to see fuel cell cars soon.

 

Related articles:
Recap for 88th ACS Colloid & Surface Science Symposium 
Highlights of 58th EIPBN Conference 
A Brief Note for ISMPC13 
2013 DOE Catalysis Working Group Meeting 

Highlights of 58th EIPBN Conference

The 58th International Conference on Electron, Ion, and Photon Beam Technology and Nanofabrication (EIPBN) was held in Omni Shoreham Hotel, Washington DC from 5/27 to 5/30, 2014. Started from 1959, this is one of the most influential conferences in the field of nanopatterning and device fabrication. Due to its main topics in electron, ion, and photon beams, EIPBN is also referred to as “3-beams” conference.

58th EIPBN 2014 banner600
58th EIPBN, or 3-beams conference

The topics include:
– Nanoimprint lithography
– Directed Self-Assembly
– Biologically-inspired Assembly
– Atomic and Molecular manipulation
– Electron- and ion-beam lithography
– Advanced optical lithography
– Dimensional metrology, alignment
– Imaging methods
– Scanned-probe-based patterning
– Resists and resist processing
– Maskless lithography
– Soft lithography and embossing
– Extreme UV lithography
– Nanoscale processing techniques

 

Selected conference highlights:

Dr. Marija Drndic’s research team at UPenn showed their fancy work of turning a transmission electron microscope into a nanosculpting device. They used JEOL 2100F TEM in STEM mode. This is exactly the same model that I used to operate everyweek in the past 3 years in NISP Lab at UMD, College Park. When well designed, the instrument can be used to monitor the in situ gold nanoparticles (Au NPs) synthetic process by measuring the current. The work was published lately last year (Nano Lett. 13, 423, 2013).

One of the eye-catching work is paper-based microscope, Foldscope, developed by Dr. Manu Prakash at Stanford University. With a stunning resolution of 0.7 micron, the microscope just cost less than $1. The Foldscope can do bright field, dark field, image projection on a screen, and can be connected to a smart phone for recording. This is a great invention from a simple idea and may impact people’s life. According to the presenter, the best applications of this microscope are field diagnostics, as well as education with extremely low cost.

paper-based microscope
Paper-based microscope. Photo from http://www.foldscope.com/

     In the commercial exhibit, SwissLitho AG demonstrated their NanoRazor. The principle is straightforward as to evaporate organic resist by heating at specific positions controlled using a scanning tip. The overall instrument is pretty much similar as a SPM with larger operating area and heating function. The computer in the exhibition hall is remotely connected with the instrument in Switzerland. By simply drawing patterns using the software or even using a pen on the writing pad, the nanostructures can be fabricated almost simultaneously. The nanopattern below was made by myself in seconds! Besides of that, it can make multiscale data storage materials.

SwissLitho600
Hand-drawn nanostructures made by a remotely controlled NanoRazor. Image received from Dr. Stefan Weber.

PS:

The 58th EIPBN conference site is located in the center of Washington, DC, within 15 min walking distance from The Smithsonian National Zoo, which is the featuring tourist spot of the city.

Links to current and previous conferences:

58th EIPBN: May 27-30, 2014 in Washington, DC. http://eipbn.org/

57th EIPBN: May 28-31, 2013 in Nashville, TN. http://eipbn.org/2013/

56th EIPBN: May 29-June 1, 2012 in Waikoloa, HI. http://eipbn.org/2012/

EIPBN abstracts archive for 2007-2014 http://eipbn.omnibooksonline.com/

 

Related articles:
Recap for 88th ACS Colloid & Surface Science Symposium 
2014 DOE Annual Merit Review Meeting (Fuel Cell Topics Recap) 
A Brief Note for ISMPC13 
2013 DOE Catalysis Working Group Meeting 

My Interview by Georgetown University on Visa Issue as a Science PhD Student

    This is a short interview by Georgetown University on the issue of immigration and residency status of international students and scholars associated with STEM (Science, Technology, Engineering, and Mathematics). The interview is one of the three which were posted on GU Office of Federal Relations Website – “Speaking Out for Georgetown on Immigration Reform”.

Earlier this year, the immigration bill was proposed. There have been lots of debates from both sides. To support international students and scholars, Georgetown University interviewed some students and researchers who have been doing important work which may have great impact to the society. I am honored to be one of them and had the opportunity to show my work in the lab.

I have been working on several projects. The one on small gold and silver nanoparticles for molecular electronics was funded by NSF and is currently in renewal. Our lab is one of the major players in this field and has published a series of high impact papers on top scientific journals. A few months ago, my mentor was invited to write a book chapter for Royal Society of Chemistry (RSC) to demonstrate our contribution to this field. I am very honored having contributed for this and became a co-author. In July, our lab had two attendees to present on an international conference where only 40 scientists and students from all over the world attend in nanoparticle research. (See “A Brief Note for ISMPC13”)

The second part of my work, the synthesis of shape-controlled nanoparticles as fuel cell and battery catalysts, has been funded by DOE for quite some years and just got renewed earlier this year. My mentor is an expert in this field and hosted an International Society of Electrochemistry (ISE) annual meeting at Georgetown in 2012.

The potential medical application that I talked about in the interview is a promising, though still yet to be implemented application. However, there have been some efforts on using gold and silver nanoparticles as drug carriers and therapeutic agents.

All of these above is to say that a lot of important and meaningful work is being carried out by international students and scholors like myself and many of my colleagues. Most of them work very hard and have made great achievements that can change people’s lives. If they have a more secure and worry-free residency status, they would be able to focus on their research and continue to contribute excellent work. Undoubtedly, it’s a win-win situation for the society and the person.

Link to the video on the Office of Federal Relations: http://federalrelations.georgetown.edu/video/yangwei-liu-h1b.html

Link to the video on YouTube: http://www.youtube.com/watch?v=HTQj8wHXuFI

SEED Project Reported on Capital Chemist

Image

    The American Chemical Society Project SEED has provided high school students an opportunity to do scientific research for 44 years. This summer, the participating institutions in Washington DC metro area include Georgetown University, George Washington University, University of Maryland at College Park and Baltimore County, Food and Drug Administration (FDA), National Institute of Standards and Technology (NIST), and the Library of Congress.

    Thanks to my supervisor, Dr. Tong, I served as one of the graduate student mentors. I worked together with Richard Castro, who is a very diligent and smart student from High Point High School, and finished the project “Metal nanoparticles synthesis and characterizations”. I was very pleasant having this chance working with him. This study is a very important preliminary work for the synthesis of shape controlled core-shell nanoparticles. The core-shell particles, if well controlled, are capable to perform higher electrocatalytic activities than mono-metallic nanoparticles for fuel cell applications.

    After the project was finished by the end of the summer, The Capital Chemist reported the achievement of the projects on its September 2013 issue (Vol. 63, No. 6). The report also included photos of research groups that participated in the project.

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A Brief Note for ISMPC13

My ISMPC13 poster on Brust-Schiffrin synthesis of Ag nanoparticles and growth mechanism study.

My ISMPC13 poster on Brust-Schiffrin synthesis of Ag nanoparticles and growth mechanism study.

Two years later since the last conference in Finland, the 3rd International Symposium on Monolayer Protected Clusters (ISMPC13) was held in Colorado State University at Pingree Park from 7/31 to 8/3. This was a small conference with concentrated topics, and was very intense and informative. There were 20+ talks and 20+ posters this year. The topics were highly focused on monolayer protected Au, Ag and other transition metal nanoclusters with catalytic and biomedical applications.

There are four main characters in this conference.

1. Most groups are using Mass Spec to characterize their NPs. Only a few provide TEM images as subsidiary information but the NPs in the images are seemingly not homogeneous, which are claimed to be attributed from the damage by the electron beam.

2. As for applications, biological imaging and therapeutics seem to be hot topics. Some groups have already started to test the excursion of Au NPs on mice. But no such studies for silver or other metals.

3. There are lots of collaborations between calculation, synthesis, and characterization groups. A good number of groups send their particles to a few other labs for Mass Spec.

4. Ag44 has become a new hot topic in Ag clusters. But all of them are in aqueous systems with aromatic ligands. This may have to do with steric effect and the electron affinity of the functional groups being used.

After all, this conference was a great opportunity to exchange information and generate ideas with colleagues who are working on the same field. The things one can learn from it are more than doing months of experiment. I look forward to the next ISMPC in Japan.

PS:

Thanks Dr. Chris Ackerson for hosting ISMPC13 and his students for providing transportation support, and Dr. Terry Bigioni and Dr. Christine Aikens for co-chairing this conference.

Links to previous and current conferences:

ISMPC08 at University of Jyvaskyla (Finland)

ISMPC11 at University of Jyvaskyla (Finland)

ISMPC13 at Colorado State University (United States)

Cabins in Pingree Park in which We lived and had conference.

Cabins in Pingree Park in which We lived and had conference.

Beautiful mountain area.

Beautiful mountain area.

The sky seems clearer at an altitude of 1.5 miles from the sea level.

The sky seems clearer at an altitude of 1.5 miles from the sea level.

 

Related articles:
Recap for 88th ACS Colloid & Surface Science Symposium 
2014 DOE Annual Merit Review Meeting (Fuel Cell Topics Recap) 
Highlights of 58th EIPBN Conference 
2013 DOE Catalysis Working Group Meeting 

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