Yunfeng Lu - US grants

With support from the Major Research Instrumentation (MRI) Program, Tulane University will acquire a growth/preparation apparatus for nanoscale and materials science. The new setup will combine a plasma source for non-invasive surface cleaning with thin film deposition equipment (physical vapor deposition, plasma-assisted vapor deposition, pulsed laser deposition) and basic in-situ characterization facilities (RHEED and XPS). The primary users will be researchers from Tulane University and Xavier University of Louisiana.

This apparatus will be used for the synthesis of a wide variety of magnetic catalytic, biocompatible, nanoscopic and structural materials, and will play a key role in integrating Tulane's and Xavier's materials synthesis and advanced surface characterization programs. It will also enhance instruction through research training of undergraduate, graduate, and post-graduate students; through implementation in several courses; and as a hands-on component in outreach programs.

This project addresses the design, synthesis, characterization, processing and applications of novel multifunctional heterogeneous catalysts for environmentally benign and high efficiency organic transformations in aqueous media. It emphasizes metallic, organometallic-complex, and multifunctional catalysts capable of catalyzing multiple reactions simultaneously, examining the activity and selectivity of the catalysts for industrially important organic reactions, and engineering the structures and catalytic chemistry to achieve optimal performance through a fundamental understanding of catalytic reactions. This multidisciplinary project involving chemistry, chemical engineering, materials science, and environmental science provides a strong opportunity to integrate research with education to address important industrial issues such as how to reduce volatile and toxic organic pollutants in the environment.

The development of new catalysts and methodologies for efficient and environmentally benign transformations of volatile organic pollutants will help achieve sustainable long-term economic growth while maintaining a cleaner industrial environment. Students trained in the synthesis, characterization, processing, optimization and recovery of catalysts will be highly competitive in both the academic and industrial job market. This Technology for a Sustainable Environment project is part of the National Science Foundation / Environmental Protection Administration partnership program. It is being jointly supported by the Office of Multidisciplinary Activities and the Division of Materials Research.

Papadopoulous, Kyriakos D., et al
Tulane University

"Confocal Viedo \ (Capillary\) Microscopy with Flourscence"

The acquisition of a deconvolution workstation, which, together with a number of attachments and software will enable researchers in the Department of Chemical Engineering at Tulane University to do confocal microscopy and sophisticated image analysis. Existing video (capillary) (fluorescent) microscopy setups in the laboratories of Kyriakos Papadopoulos and Kim O.Connor have been used by all participating investigators, and this upgrade will significantly impact their individual and joint research projects that rely on microscopy.

Broader Impacts:

The PIs will use this acquisition to visualize and quantify interfacial processes that are important in drug delivery schemes involving double emulsions, liposomes, and pheroidal aggregates of cancer cells. Additionally, the equipment will be very useful in the ability to develop a capillary microscopy technique that will visualize phenomena at high temperatures, and will also make possible the quantification of luminescence in nanowires and of transport of Dense Non-Aqueous-Phase Liquids in model porous media that simulate contaminated soils.

Tulane enjoys very strong research and educational ties with Xavier University, a major minority institution in the southern United States. Kyriakos Papadopoulos has had a continuous collaborative research project with Xavier Physics Professor Elia Eschenazi, which has involved many undergraduates and which has led to three Tulane Chemical Engineering MS degrees awarded to students who had previously majored in Chemistry at Xavier. Additionally, the PI's fully participate in the Louisiana Alliance for Minority Participation (LAMP), a comprehensive, statewide program aimed at substantially increasing the number and quality of minority students earning bachelor's degrees in science, mathematics, engineering and technology (SMET) areas. In the last 2 years, Vijay John has supervised three students through this program (Jonathan Hijuelos and Hendekea Azene from Tulane, Stephanie Sigers from Dillard University). The program is sponsored through an NSF grant to the State of Louisiana. The investigators are committed to continuing their research collaboration with Xavier, thus providing educational opportunities to the students of that University.

John, Vijay T.
Tulane University

"Environmental Remediation through Self-Assembly and Applications to Environmental Sensor Development"

The objective of this research is to develop a process for environmental remediation of aqueous streams containing aromatic compounds. The process involves incorporating well-known technologies with new science. Surfactant micelles will be first used to concentrate organic contaminants (typically phenols and aromatic amines) in aqueous streams, in a version of the well-studied micellar enhanced ultrafiltration technology (MEUF). The next step will be to polymerize these contaminants within the micelles using oxidative enzymes such as horseradish peroxidase. The resulting conjugated polymers are themselves very useful in coatings technologies, and in applications to electrooptics. The third step is to encapsulate the micelle-polymer assembly within the pore structure of mesoporous silicas (and titanias). This will result in useful polymer-ceramic nanocomposites where functionality of the encapsulated materials can be utilized to develop robust sensor materials that are photoluminescent. The encapsulation of enzymes through this route will also be evaluated in the development of novel chemo-biosensors.

Broader impacts

Excellent interdisciplinary training for both undergraduates and graduate students will be provided. The combination of spectroscopy, microscopy and scattering techniques that the students will be exposed to, will be an invaluable research experience. Tulane University operates a unique Coordinated Instrumentation Facility where centralized instrumentation and expertise allow excellent student training. The PI's are fully committed to providing educational opportunities, and have a strong record of working towards such objectives with formalized programs such as the Louisiana Alliance for Minority Participation in Research (LAMP). The research is the continuation of a collaboration at Tulane that has produced several Ph.D. graduates and has provided undergraduate research experience to over 10 students. From a technical prospective, the exploratory research phase will evaluate the feasibility of transforming environmental contaminants to useful, high value products.

The process of enzyme entrapment in mesoporous silicas will be used to encapsulate phosphotriesterase. Thin films of such enzyme containing silicas will be used to develop a sensor for the detection of nerve agent surrogates such as paraoxon.

Lu, Yunfeng
Tulane University

"CAREER: Synthesis and Device Applications of Continuous Hierarchical Nanowire/mesh Thin Films"

Nanotechnology is able to manipulate individual atoms and molecules to create large structures with improved properties and functions. In addition to the research, the continuous growth of nanotechnology requires nanotechnology education, workforce training, and public information on related issues. The research of this project includes the following goals and objectives: 1) to develop a general synthesis approach for the fabrication of nanowire and nanomesh thin films with controlled hierarchic structure and composition; 2) to examine their unique properties; and 3) to explore their applications, such as sensor and photovoltaics.

Broader Impacts:
Nanoscale materials like nanowires often show novel and significantly improved physical, chemical, and tribological properties and functions. Current synthesis methods are often inefficient and synthesized nanowires often lack the macroscopic morphology control required for device applications. The most significant scientific impact of this project is the capability to fabricate metallic or semiconductor nanowires/meshes into the continuous, macroscopic, hierarchical thin films necessary for direct device applications. The findings gained from this project will contribute to the basic understanding of the nanoscale physical and chemical phenomena, providing insights into the design and fabrication of high-sensitivity sensors and high-efficiency photovoltaics. The fundamental studies of the confined electrodeposition within the mesoscale geometries will significantly contribute to current electrodeposition knowledge. The research could develop a general synthesis method of fabricating continuous hierarchical metallic and semiconductor nanowire/mesh thin films, examine their unique properties, and explore their sensor, fuel cell, photovoltaic, and other applications. The proposed nanostructured sensors may possess the high-sensitivity needed for homeland security missions. The proposed photovoltaic devices could directly contribute to our national energy security by providing low-cost, high-efficiency energy devices.

The success of this career-development plan could have broad impacts on nanotechnology education in the southern region by providing workforce training, disseminating nanotechnology information, and nurturing the research infrastructure. This project could develop a highly integrated career-development plan in nanotechnology research and education. The PI will focus on improving education in this region through course offerings, research programs covering K-12 to graduate students, conferences, and industrial collaborations.

The scanning electron microscope system will be used to carry out a wide range of innovative research projects ranging from the understanding of nanomaterials to the fine structures inherent in biological systems. In the nanomaterials research, the instrument will be used to examine the structure of thin films and extended hierarchical structures. These studies will lead to the development of new catalysts and membranes, photovoltaic and thermoelectric devices, and in the development of lightweight composite structures. The studies will also lead to new avenues to manufacture nanostructured materials. In biology, the research will help define the fine structures of freshwater fishes, such as tail neuromasts in darters and lip-surface anatomy in suckers, in order to refine their taxonomy and systematics. This work will lead to a better understanding of freshwater fish biodiversity in North America.

The proposed instrument acquisition will greatly improve the infrastructure for research and education at Tulane University. It will be housed in the Coordinated Instrumentation Facility (CIF) at Tulane, which is a facility that operates and maintains university-wide shared instrumentation. The instrument will be available to the entire university community and will enhance excellence in graduate and undergraduate education at Tulane. The proposed instrument will be used in training and class demonstrations and will provide research opportunities for both undergraduate and graduate students. This acquisition will play an important role in encouraging the participation of underrepresented groups in the areas of science and engineering, through such existing programs as the Louisiana Alliance for Minority Participation (LAMP), the Tulane/Xavier combined degree program, and the Graduate Alliance Program (GAELA). In addition, this acquisition will help to attract high-quality students and faculty to Tulane University.

Lu, Yunfeng
Tulane University

"NER: Hydrogen Separation by Hierarchical Palladium/Inorganic Nanocomposite Membranes"

Hydrogen separation is a key component of the future hydrogen energy economy. Hydrogen separation membranes constitute the forefront in this field because of their low cost and applicability to high temperature feedstreams in refineries. However, before wide-scale commercial implementation can occur, more durable and efficient membranes must be synthesized in an inexpensive and simple manner.

This experimental research directly addresses these challenges by developing nanostructured palladium alloy/ inorganic membrane assemblies with improved membrane mechanical stability, lower overall membrane costs, and significantly improved hydrogen permeability and selectivity. Devices will be fabricated using template-assisted electrodeposition inside surfactant templated mesoporous silica layers that have controllable, ordered pore structures. The electrodeposition of palladium and palladium alloys produces a thin, dense, nanocrystalline metal/ silica nanocomposite with hierarchical structural control on an alumina membrane support. The unique properties endowed by the nanoscale palladium structure will result in enhanced hydrogen transport properties due to new diffusion pathways. A molecular dynamics mathematical model will describe the hydrogen transport in the bulk, in the grain boundaries, and on the internal metal surface. This study will provide a fundamental understanding of the different routes and mechanisms for diffusion through a nanoscale material. The knowledge gained can be applied to other nanomaterial projects and future membrane applications.

Success of this project will directly answer the current hydrogen separation challenges and prepare this field for the future hydrogen energy economy. All results from this research will be quickly disseminated to the general public in the form of peer reviewed journal articles and presentations at national scientific conferences. The educational plan is built on general teaching techniques and available education infrastructure in the area. Because of limited nanotechnology funding and education in the area, the PI will focus on improving education in this region through nanotechnology programs, courses, and conferences. The educational program will focus on the unique properties of nanomaterials, laboratory and industrial synthesis techniques, advanced device fabrication, and possible solutions to our energy needs through nanotechnology. This project will incorporate Nanoscale science and engineering (NSE) education into the current department curriculum in order to prepare students to become the future, as well as the present, technological workforce.