Dr. Jennifer I. Brand, Professor
Chemical & Biomolecular Engineering
Engineering Research Center
University of Nebraska-Lincoln
Lincoln, Nebraska 68588-0511
The Brand Laboratory is a traditional chemical engineering research group, investigating both new materials and new, more efficient materials production processes for thin films, microfibers (10 µm) and microparticles of commercial importance. The specific applications for these materials are radiation detection, advanced semiconductor and electronics devices, corrosion and wear resistant coatings, and catalytic support systems, with product morphology and performance controlled by process parameters. Current investigations are ongoing in three areas: supercritical processing, solid-state radiation detetectors, and polymers for harsh environments.
Supercritical processing. Oxides and diamond-like carbon (DLC) films have been grown from a clean, environmentally-friendly process, using only ultra-pure supercritical water and inorganic precursors, such as graphite as the raw materials in a free-jet expansion deposition system. This deposition system is one of the few facilities in the world where solutions of high-temperature, high-pressure water and inorganic materials are studied, and it is unique in its capacity for varying both the electrochemical and physical environments to explore fundamental electrochemical phenomena in flowing deposition processes. Electrochemical effects and manipulating the electrochemical environment have recently been shown to be important. Resulting films have been robust, adhered well to a variety of substrates (metals, polymers, and silicon), and have definitely undergone a dissolution and subsequent precipitation, as shown by mass spectrometry, FTIR and electron diffraction and spectroscopy of the deposited films. Particles and microfibers have been produced in the same system by careful control of processing conditions. To predict and control product morphology as a necessary step to commercialization, we have developed a detailed process model, relating the thermodynamics, fluid mechanics, mass transport, electrokinetics and reaction and condensation kinetics to film and particle morphology, crystallinity, and uniformity.
The fundamental knowledge of electrochemical effects in flowing systems has broader applications than the processing of high quality electronic materials. Results of this research on the electrochemical behavior of the high-temperature, high-pressure flowing aqueous solutions can be applied to the prevention of corrosion in power plants, and to geochemical processes, both for the understanding of natural mineral formation and for evaluating feasibility of geothermal energy recovery.
Solid-state Radiation Detection. We make novel semiconducting materials, based on gadolinium oxide and boron carbide semiconducting materials, fashion them into electronic devices, and successfully detect neutrons with them, while excluding signals from background gamma radiation. The properties of these materials are tailored by alloying them with other elements such as transition metals and rare earths, and other elements are exclude signals from other radiations. We discovered the neutron-detecting heteroisomeric diode, by exploiting the differences in compounds with the same elemental make-up but in different arrangements, (isomers, which can have very different properties, e.g. polyethylene and polypropylene). This device, made from only boron and carbon, can be used to generate power from light, neutrons, and alpha radiation. Fundamental studies of the new materials include spectroscopic characterization performed at UNL and at the UNL Synchrotron Beamline at CAMD, LSU campus, Baton Rouge, LA.
Results of this research have space, anti-terrorism, nuclear industry, and high-temperature semiconductor applications, as well enhancing the fundamental understanding of the III-IV semiconductors and rare-earth compounds.
Polymers for harsh environments. Novel polymer materials for harsh environments are also being investigated. In addition to predicting and evaluating performance in harsh environments and specialized applications, novel polymers, including bio-based polymers, are being developed and fabricated.
“The local structure of transition metal doped boron carbides”. Jing Liu, Gunagfu Luo, Wai-Ning Mei, Orhan Kizilkaya J.I. Brand and P.A. Dowben. Submitted to Journal of Physics D, October 2009. In review.
“The K-shell Auger Electron Spectrum of Gadolinium Obtained Using Neutron Capture in a Solid State Device” David Schultz; Bryan Blasy; Juan Colon Santana; J.C. Petrosky; J.W. McClory; D. LaGraffe; J.I. Brand; Jinke Tang; Wendong Wang; N. Schemm; S. Balkir; M. Bauer; I. Ketsman; R.W. Fairchild; Ya. B. Losovyj; and P.A. Dowben. Revised version submitted to J. Physics D. 12 09 2009.
“Cubic Gadolinium Oxide Thin Films from Supercritical Water”. J. A. Colón Santana, Ning Wu, Jie Xiao, Pamela Jeppson, Peter Molnar, J. I. Brand. Submitted to Thin Solid Films. 2009
“Gd-doping of HfO2” Ketsman, Ihor; Losovyj, Ya. B.; Sokolov, A.; Tang, Jinke; Wang, Zhenjun; Natta, M. L.; Brand, J. I.; Dowben, P. A. Applied Surface Science (2008) 254(14), 4308-4312.
“Doping of boron carbides with cobalt, using cobaltocene” L. Carlson, D. LaGraffe, Snjezana Balaz, A. Ignatov, Ya. B. Losovyj, J. Choi, P.A. Dowben, and J.I. Brand,, Applied Physics A 89 (2007) 195-201
“A Hand-Held Neutron Detection Sensor System Utilizing a New Class of Boron Carbide Diode", IEEE Sensors Journal, K. Osberg, N. Schemm, S. Balkir, J.I. Brand, S. Hallbeck, P. Dowben, M.W. Hoffman. 6(6), 1531-1538, 2006
“The All Boron Carbide Diode Neutron Detector: Comparison with Theory” S. Balkir, Nathan Schemm, Kevin Osberg, R.W. Fairchild, Abhinandan Pattanayak, Myriam S. Bikah, J.I. Brand, A.D. Harken, B.W. Robertson, A.N. Caruso, and P.A. Dowben. Materials Science and Engineering B 135, pp. 129-133, 2006.
Ph.D. Degrees Supervised to Completion
Ali O. Sezer, Ph.D. Aug. 2003. “The Effect of Electrochemical Phenomena on the Deposition of Carbon Containing Inorganic Thin Films from Supersonic Expansion of Aqueous Supercritical Solutions”.
Snejzana Balaz, Ph.D. May 2007."Electronic Structure and Evolution of Dehydrogenation of orthocarborane, metacarborane, paracarborane, orthophosphacarborane, and meta-phosphacarborane".
Marcus L.Natta, Ph.D. Aug. 2008. "Fabrication and Characterization of Novel Boron and Gadolinium Rich Power Generation and Real-time Neutron Detection Materials and Devices".
M.S. Degrees Supervised to Completion
John W. Guerry, M.S. May 1996. "The Deposition of Aluminum Oxide and Diamond Films through the Rapid Expansion of Supercritical Solutions”.
Ali O. Sezer, M. S. Dec. 1997. "The Effect of Oxygenated Compounds on the Vapor Pressure of Hydrocarbons".
Stacey D. Uden, M.S. Dec. 1999. “Process Control of a Batch Distillation with Rectification in an Undergraduate Laboratory”.
Darlene Larson Hug, M.S. Dec. 1999. “Modelling and Moiré Deflectometry Analysis of the Free-jet Expansion Flow Profile of Supercritical Water”.
Lonne Blecha, M.S. Dec.2000. “Direct-Sampling Mass Spectroscopy of a Free Jet Expansion of a Supercritical Water Solution”.
Ravi Babu Billa, M.S. Jan. 2000. “Semiconducting Boron Carbide Heteroisomeric Diode: Fabrication and Characterization”.
Petru Lunca-Popa, M.S. Jan.2005. Non-thesis option.
+ 25 Undergraduate Researchers