Previous Meetings
MRS October Meeting 2009
Mark Luo
Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC
Fabricating Nanocomposite Electrodes through Interfacial Fusion of Metallic Nanoparticles
Fusion of metallic nanoparticles at both surfaces of silica colloids and nanoporous bulk materials has been utilized as an effective method to integrate inorganic and organic components into nanocomposite materials. When performed on substrates that have been modified with aprotic functional groups, aminosilica colloids doped with metallic nanoparticles adhere to the substrates and self-assemble into nanocomposite film with its thickness being the function of the time. This is made possible through ethylenediamine functional groups on the aminosilica colloids. In contrast, without metal-bound functional groups, fusion of metallic nanoparticles can be induced at the interface of nanoporous silica composite when polymer is utilized as the mobile phase. Formation, mobilization, and fusion of metallic nanoparticles within the polymer phase can be simultaneously induced at 160?C, during which reactions alter the physical appearance of the materials from transparent to silver metallic color. These two fusion methods are suitable to create the functional structures through either soft-lithography or microcontact-imprinting that exhibit enhanced electrochemical property.
MRS April Meeting 2009
S.C. Bharath, T.P. Pearl.
Department of Physics, North Carolina State University, Raleigh NC
Characterization of molecular and atomic species on ferroelectric and semiconductor surfaces
Metal on ferroelectrics has recently gained a great deal of interest as a system for catalysis applications. For the purpose of revealingthe mechanisms involved with metal deposition on ferroelectric oxide surfaces, single crystalline lithium niobate (LiNbO3, LN) `Z-cut'along the (0001) plane, has been prepared and characterized and subsequently exposed to gold (Au) atoms. Au atoms deposited on (0001) LN was chosen as a model system for this study. In an effort to exploit the interaction of the Au atoms on the LN surface, very low coverage on the order of atomic layers was explored. Consequently, atomically flat LN was prepared as a canvas for supporting atomic layer gold films. Low-energy electron diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, and Auger electron spectroscopy were used to characterize the surface of LN as well as the nature of the Au films grown on the LN surface. These Au atomic layers were grown, via metal evaporation, and characterized under UHV and ambient conditions. Understanding the growth mechanism of Au films on uniformly poled ferroelectric surfaces permits for a more complete understanding of how ferroelectric surfaces can be used for controlling growth and assembly. This will in turn lend to tuning more efficient applications of the metal on ferroelectric system.
Vinayak Rastogi and Orlin D. Velev
Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh NC.
Microdroplet Engineering for Microbioassay and Synthesis of Functional Structured Porous Particles
We present methods which employ sessile or suspended microdroplets to develop applications in the areas of bio-detection, photonics, drug delivery and catalysis. The first technique we report is for droplet-on-a-chip microbioassays.1 The assays are performed in droplet micro-containers suspended on the surface of high density fluorinated oil and are based on the process of agglutination of antibody-coated particles. Droplet microbioassays for the detection of Ricin were designed and their performance was compared to the standard handheld field assays. These droplet microbioassays were found to be 10 times more sensitive in terms of analyte concentration while requiring 100 times less sample volume. We developed a model for the agglutination kinetics and mass transfer process inside the droplets, which correlates well with the experimental data.
The second technique that we developed uses droplet templates dispensed on superhydrophobic substrates for the fabrication of a new class of anisotropic particles. 2 We produced both shape-anisotropic and composition-anisotropic supraparticles. The shape anisotropy was demonstrated by fabricating "doughnut" assemblies using droplets of both pure silica suspensions and silica mixed with gold nanoparticles. The composition anisotropy was realized by redistribution of the magnetic nanoparticles in droplets containing mixtures of latex and magnetic particle suspensions. The redistribution is dictated by the pattern of magnetic field to which the droplet templates are introduced during drying. We developed new types of patchy magnetic particles that can find application in targeted drug delivery. The latex matrix can be infused with a drug and the magnetic patch(es) facilitate remote manipulation of the carrier. A new microfluidic chip is used for the characterization of drug/material release rate from porous latex network. An experimental and theoretical study of the rate of release of drug from these particles is underway.
References:
1 Rastogi, V. and Velev, O. D., Biomicrofluidics 1 (1), 014107 (2007).
2 Rastogi, V. et al., Advanced Materials 20 (22), 4263 (2008).
MRS March Meeting 2009
Dr. Stoyan Smoukov from the Chemical & Biomolecular Engineering department
Janus Nanoparticles
MRS February Meeting 2009
Dr. Steven Shannon from the Nuclear Engineering department
What is a plasma, how do you make one, and how does it interact with my nano-bio-memsy device?
Material deposition and patterning with low temperature plasmas has been a cornerstone of micro and nano-scale manufacturing.
This presentation will look at how plasma technology has evolved over the years to enable manufacturing of devices down to the nano-scale, and look at some of the work being done at North Carolina State to further extend the capabilities of this truly unique material processing technology.
MRS October Meeting 2009
Mark Luo
Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC
Fabricating Nanocomposite Electrodes through Interfacial Fusion of Metallic Nanoparticles
Fusion of metallic nanoparticles at both surfaces of silica colloids and nanoporous bulk materials has been utilized as an effective method to integrate inorganic and organic components into nanocomposite materials. When performed on substrates that have been modified with aprotic functional groups, aminosilica colloids doped with metallic nanoparticles adhere to the substrates and self-assemble into nanocomposite film with its thickness being the function of the time. This is made possible through ethylenediamine functional groups on the aminosilica colloids. In contrast, without metal-bound functional groups, fusion of metallic nanoparticles can be induced at the interface of nanoporous silica composite when polymer is utilized as the mobile phase. Formation, mobilization, and fusion of metallic nanoparticles within the polymer phase can be simultaneously induced at 160?C, during which reactions alter the physical appearance of the materials from transparent to silver metallic color. These two fusion methods are suitable to create the functional structures through either soft-lithography or microcontact-imprinting that exhibit enhanced electrochemical property.
MRS April Meeting 2009
S.C. Bharath, T.P. Pearl.
Department of Physics, North Carolina State University, Raleigh NC
Characterization of molecular and atomic species on ferroelectric and semiconductor surfaces
Metal on ferroelectrics has recently gained a great deal of interest as a system for catalysis applications. For the purpose of revealingthe mechanisms involved with metal deposition on ferroelectric oxide surfaces, single crystalline lithium niobate (LiNbO3, LN) `Z-cut'along the (0001) plane, has been prepared and characterized and subsequently exposed to gold (Au) atoms. Au atoms deposited on (0001) LN was chosen as a model system for this study. In an effort to exploit the interaction of the Au atoms on the LN surface, very low coverage on the order of atomic layers was explored. Consequently, atomically flat LN was prepared as a canvas for supporting atomic layer gold films. Low-energy electron diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, and Auger electron spectroscopy were used to characterize the surface of LN as well as the nature of the Au films grown on the LN surface. These Au atomic layers were grown, via metal evaporation, and characterized under UHV and ambient conditions. Understanding the growth mechanism of Au films on uniformly poled ferroelectric surfaces permits for a more complete understanding of how ferroelectric surfaces can be used for controlling growth and assembly. This will in turn lend to tuning more efficient applications of the metal on ferroelectric system.
Vinayak Rastogi and Orlin D. Velev
Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh NC.
Microdroplet Engineering for Microbioassay and Synthesis of Functional Structured Porous Particles
We present methods which employ sessile or suspended microdroplets to develop applications in the areas of bio-detection, photonics, drug delivery and catalysis. The first technique we report is for droplet-on-a-chip microbioassays.1 The assays are performed in droplet micro-containers suspended on the surface of high density fluorinated oil and are based on the process of agglutination of antibody-coated particles. Droplet microbioassays for the detection of Ricin were designed and their performance was compared to the standard handheld field assays. These droplet microbioassays were found to be 10 times more sensitive in terms of analyte concentration while requiring 100 times less sample volume. We developed a model for the agglutination kinetics and mass transfer process inside the droplets, which correlates well with the experimental data.
The second technique that we developed uses droplet templates dispensed on superhydrophobic substrates for the fabrication of a new class of anisotropic particles. 2 We produced both shape-anisotropic and composition-anisotropic supraparticles. The shape anisotropy was demonstrated by fabricating "doughnut" assemblies using droplets of both pure silica suspensions and silica mixed with gold nanoparticles. The composition anisotropy was realized by redistribution of the magnetic nanoparticles in droplets containing mixtures of latex and magnetic particle suspensions. The redistribution is dictated by the pattern of magnetic field to which the droplet templates are introduced during drying. We developed new types of patchy magnetic particles that can find application in targeted drug delivery. The latex matrix can be infused with a drug and the magnetic patch(es) facilitate remote manipulation of the carrier. A new microfluidic chip is used for the characterization of drug/material release rate from porous latex network. An experimental and theoretical study of the rate of release of drug from these particles is underway.
References:
1 Rastogi, V. and Velev, O. D., Biomicrofluidics 1 (1), 014107 (2007).
2 Rastogi, V. et al., Advanced Materials 20 (22), 4263 (2008).
MRS March Meeting 2009
Dr. Stoyan Smoukov from the Chemical & Biomolecular Engineering department
Janus Nanoparticles
MRS February Meeting 2009
Dr. Steven Shannon from the Nuclear Engineering department
What is a plasma, how do you make one, and how does it interact with my nano-bio-memsy device?
Material deposition and patterning with low temperature plasmas has been a cornerstone of micro and nano-scale manufacturing.
This presentation will look at how plasma technology has evolved over the years to enable manufacturing of devices down to the nano-scale, and look at some of the work being done at North Carolina State to further extend the capabilities of this truly unique material processing technology.
An Interview with Dr. Baliga ApnaTriangle.com recently sat down with Dr. Jayant Baliga to discuss his role in the semiconductor revolution. Dr. Baliga on his early l... |
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NanoDays 2009 The seventh annual NanoDays, a statewide initiative designed to present the world of nanoscale science and nanotechnology to the public, particularly K... |
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Misra Awarded for Engineered High-K Dielectrics and Metal Electrodes Veena Misra has been awarded $120,000 by the Intel Corp. for research on Investigation of En... |
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New "Green" Undergraduate Concentration Added North Carolina State University's Department of Electrical and Computer Engineering will offer a new undergra... |
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