Center for Nanophase Materials Sciences

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The Center for Nanophase Materials Sciences(CNMS) was the first to open of the five Nanoscale Science Research Centers the United States Department of Energy sponsors. The Center's location is in Oak Ridge, Tennessee. The CNMS is a collaborative nanoscience user research facility for the synthesis, characterization, theory/ modeling/ simulation, and design of nanoscale materials and is co-located with Spallation Neutron Source.

Overview[edit]

The Center for Nanophase Materials Sciences (CNMS) at Oak Ridge National Laboratory (ORNL) is one of five nanoscience research centers (NSRCs) funded by the U.S. Department of Energy (DOE) Scientific User Facilities Division. It provides a diverse user community – predominantly in the US but also internationally - with access to state-of-the-art nanoscience research capabilities, expertise, and equipment. The scientists at the CNMS also drive a world class science program with emphasis in theory and simulation, nanofab¬rication, macromolecular synthesis and characterization, and understanding of structure, dynamics and functionality in nanostructured materials using scanning probe microscopy, neutron scattering, optical spectroscopy, and soft-matter electron and helium ion microscopy. The CNMS annually hosts more than 400 unique users who respond to its biannual proposal calls. The vibrant and growing CNMS user community conducts research addressing a vast array of science and technology questions, drawing on support from an equally broad array of funding agencies. Members of the community represent academia (>50%); national laboratories (~35%); international institutions (~10%); and industry (~4%).

The CNMS carries out its mission of delivering both user support and an outstanding science program with a focus on three research themes:

• Electronic and Ionic Functionality on the Nanoscale seeks to understand behaviors of electronic and ionic materials at the scales of defects, nanostructures, and microstructures.

• Functional Polymer and Hybrid Architectures seeks to understand and control the multiscale organization of designed macromolecular and hybrid nanomaterials, to achieve functionality capable of capturing, transporting, and transforming energy.

• Collective Phenomena in Nanophases seeks to understand collective phenomena that arise from correlations, fluctuations, nanoscale confinement and integration across length and time scales, as well as how to control these phenomena to produce complex functionality.

The CNMS takes advantage of the distinctive capabilities of other DOE user facilities at ORNL, including the Oak Ridge Leadership Computing Facility (OLCF), the Spallation Neutron Source (SNS), the High Flux Isotope Reactor (HFIR), and the Shared Research Equipment Collaborative Research Center (ShaRE). The CNMS is a critical center for advancing nanoscience throughout the scientific community in partnership with users from national laboratories, universities, and industry.

Background[edit]

The first of DOE’s five nanoscience research centers (NSRCs), the CNMS received jumpstart funding beginning in 2004 to initiate its research and user program during facility construction and went into full-scale operation on October 1, 2005. As a DOE NSRC, the CNMS maintains a simultaneous focus on serving a diverse nanoscience user community and performing high-impact nanoscale science research. CNMS staff and users conduct research together, including synthesis, characterization, and modeling of new materials. The concept for the CNMS was developed to exploit ORNL’s signature strengths in materials sciences (including polymer synthesis), neutron sciences, and computational sciences and its state-of-the-art imaging capabilities.

CNMS pioneered the integration of theory and computation into its research and user programs, an approach adopted by the other NSRCs. As illustrated schematically in Fig. 1, the science program evolves in response to grand challenges in nanoscience, emerging ORNL capabilities, and input from stakeholders. These stakeholders include the broad scientific community, as represented by the CNMS Advisory Committee; the CNMS user community, as represented by the User Executive Committee; and DOE, which has provided guidance in triennial reviews conducted in 2006 and 2009.

The CNMS User Program[edit]

The CNMS serves a diverse user community, from students who work closely with its staff, learning skills from experts and gaining access to unique instrumentation as they advance their research, to “partner users” who collaborate with staff to develop new capabilities and instruments that are then made available to the broad CNMS user community. Reflecting DOE’s charge to the NSRCs to provide both a world-class user facility and a world-leading research program, CNMS staff members on average spend half their time supporting user projects.

User projects are selected from proposals submitted in response to biannual proposal calls. Prospective users submitted nearly 1000 proposals in the period 2008-2012, with an approval rate of 64%. Each proposal undergoes preliminary vetting for feasibility regarding CNMS research capabilities and environ¬mental, safety, and health (ES&H) requirements and is then submitted to a panel of reviewers external to CNMS and ORNL. Reviewers assess the likelihood that a proposal will result in significant scientific or technological impact and determine the need for the specialized capabilities or unique expertise of the CNMS, without regard to the proposal’s subject area or alignment with CNMS scientific themes. As a result, user projects have included topics as diverse as the search for extrasolar planets and understanding chemical processes leading to the origin of life in undersea hydrothermal vents. Approximately 50% of CNMS users identify the subject area of their project as materials science; subjects such as physics, chemistry, life sciences, medical applications, earth and environ¬mental sciences, and engineering are also well represented. Each year the CNMS supports approximately 400 unique users from more than 100 different institutions spanning academia to industry and from around the world.

The CNMS Science Program[edit]

The CNMS science program is organized around three research themes:

• The overarching goal of the Electronic and Ionic Functionality on the Nanoscale (EIFN) theme is to explore electronic and ionic material functionalities on the atomic scale and extend this knowledge to the emergent behaviors at the scales of individual nanoparticles and defects and finally to the macroscale, where function can be translated into new technologies. We aim to harness this knowledge to understand and control fundamental mechanisms of coupling between electronic and ionic functionalities that underpin catalysis and electrocatalysis, bias-induced phase transitions, transport, and energy storage and conversion.

• The Functional Polymer and Hybrid Architectures (FPHA) theme is home to our world-class synthetic macromolecular capabilities and our complementary efforts in designing functional materials, including those with hybrid molecular architectures, for next-generation energy technologies, such as organic photovoltaics. Its overarching goal is to understand how to design and control the nanoscale organization of macromolecular nanomaterials and hybrid nanocomposites to achieve novel structure, properties and functionality.

• The Collective Phenomena in Nanophases (CPN) theme focuses on the central role of fluctuations in understanding function in complex nanoscale systems, and the importance of correlations as atomic-scale systems grow to nanoscale materials. The experimental characterization and exploitation of collective phenomena in diverse systems, with theoretical description leading to understanding and control, are the cornerstone research activities in this theme. The CPN theme is where our bio-inspired nano research is performed. By understanding how nature has not only overcome fluctuations at the nanoscale, but exploited them to create functionality at low energy and with minimal resources, our goal is to inform our design of new functional nanoscale systems.

Each theme has at its core the signature CNMS strengths. EIFN draws most heavily on scanning probe capabilities; for FPHA, macromolecular synthesis (both polymeric and two-dimensional organic synthetic assembly) and functional characterization via optical, neutron, and electronic measurements are essential; and for CPN, key resources include theory, computation, and bio-inspired nanotechnology.

The goals of the CNMS science program are to conduct world-leading research at the frontiers of nanoscale science and to provide the CNMS user community with access to the capabilities generated by this research. The fraction of CNMS publications in high-impact journals has more than doubled since 2007 and its number of publications annually continues to rise – at nearly 250 in 2012.

One example of the impact of the CNMS science program can be found in the unparalleled string of accomplishments in the development and application of scanning probes delivered by EIFN researchers. New capabilities include a variety of ambient (i.e., non-UHV) scanning probes, such as piezoresponse and electrochemical strain microscopy and even ambient (liquid) environments, that are especially relevant to analyzing novel energy storage systems. Many of these developments have been licensed to scanning probe manufacturers, particularly Asylum Research, and made available in the user program.

Computational researchers in the CPN theme predicted a neutron resonance in high-Tc superconductors that was later confirmed in neutron scattering experiments at SNS. Codes developed by CNMS computational researchers are being used to build the Computational Nanoscience Endstation, a software repository containing internally developed and other public domain codes relevant to nanoscience and optimized for leadership-class computing. CPN researchers have become world leaders in bio-inspired nano through the development of advanced nanofluidic and fabrication techniques that can be used to study quantitatively nanofabricated systems that examine the effects of nanoscale crowding, reactions, and signaling/communication that occur in cells. The capabilities developed to enable bio-inspired nanoscience and technologies are made available to the user program.

The specialized macromolecular (conjugated block co-polymer, dendrimer and functionally modified peptide) synthesis capabilities within the FPHA theme are hugely oversubscribed. These include deuteration capabilities available in only a handful of groups worldwide and nowhere else in a transparent, peer-reviewed user proposal framework. As one example of the power of such synthesis, in a multidisciplinary collaboration with neutron science colleagues, small-angle neutron scattering on selectively deuterated (either core or shell) G5 dendrimers allowed the first experimental resolution of a long-standing debate about the “dense core” or “dense shell” structure of such molecular systems, unambiguously finding in favor of the former.

The perpetual cycle of scientific advances resulting in new discoveries and unique capabilities that attract high-profile users—who in turn help to inspire new CNMS scientific directions—is one of the most compelling features of the CNMS, and is at the heart of why a staff position in the CNMS is so attractive to many researchers.

CNMS Synergies with ORNL User Facilities[edit]

The balanced in-house science/user support model of the CNMS has a critical enabling and facilitating role to play in connection with scientific applications linking high-performance computing (HPC) and neutron sciences. Many staff in the CNMS Nanomaterials Theory Institute (NTI) are matrixed with the ORNL Computing and Computational Sciences Directorate, applying the computational endstation model (engaging a critical mass of staff not only in building and honing selected scientific application codes, but also in driving the scientific applications themselves) to nanoscience and neutron science for highly efficient implementation at ORNL’s world-leading HPC facilities. The CNMS also enjoys a highly productive and complementary relationship with the electron microscopy user facility, ShaRE, wherein low-dose microscopy is pursued at CNMS to complement its strong soft matter capabilities and higher dose microscopy is performed at ShaRE. The productivity of this vision is well demonstrated in Fig. 2, which shows joint publications for CNMS and other user facilities (ShaRE: Shared Research Equipment Collaborative Research Center; OLCF: Oak Ridge Leadership Computing Facility; SNS: Spallation Neutron Source; HFIR: High Flux Isotope Reactor) in 2010–2012.

CNMS Synergies with Academia and Industry[edit]

The CNMS user program acts as a catalyst for dynamic and synergistic exchanges between the highly multidisciplinary CNMS science program and users from universities and industry. These exchanges influence some directions within our science and vice versa: both CNMS science and that of the user benefit and evolve through this interactive cycle. One new and highly impactful offshoot of CNMS science is the band excitation technique developed by the CNMS scanning probe microscopy team in partnership with dozens of research groups; this technique has now been commercialized. Engaging with the CNMS can also bring profound benefits to individual academic principal investigators (PIs) who are developing research programs; we have already seen examples of more than one academic generation working with the CNMS and its sister NSRCs.

The CNMS Today and Going Forward[edit]

The CNMS has developed into a vital enabling hub for nano¬science research activities at ORNL, executing its own science program and facilitating science at other user facilities (e.g., OLCF, SNS, and HFIR). In selected areas (theory, soft matter synthesis and scanning probe microscopy), it has assembled the critical mass needed for systematic and comprehensive method development within a state-of-the-art science program—something that is rarely achieved. It brings together a fascinating diversity of multidisciplinary scientific expertise, creating an environment to stimulate scientific break¬throughs through synergistic inputs from staff scientists and users. This dynamic environment also provides an intense and stimulating experience for students and postdoctoral researchers, allowing them to broaden their experience and contacts while advancing their user projects.

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