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- Porous silicon (7)
- Etching (4)
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- Metal nanoparticles (3)
- Stain etching (3)
- 3D printing (2)
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- Metal assisted etching (2)
- Metal-assisted etching (2)
- Nanostructures (2)
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- Photocatalysis (2)
- Photoluminescence (2)
- Reaction dynamics (2)
- Silicon (2)
- AGENT (1)
- Ag|AgCl (1)
- Alkali Metal Gallium Borates (1)
- Anhydrous Fluoride (1)
- Annatto (1)
- Anodic dissolution (1)
- Anodization (1)
- Apparent quantum efficiency (1)
- Applied surface science (1)
- Aqueous methanol (1)
- Arginine (1)
Articles 1 - 30 of 70
Full-Text Articles in Physical Sciences and Mathematics
Silica Particles Convert Thiol-Containing Molecules To Disulfides, Yangjie Li, Kurt W. Kolasinski, Richard N. Zare
Silica Particles Convert Thiol-Containing Molecules To Disulfides, Yangjie Li, Kurt W. Kolasinski, Richard N. Zare
Chemistry Faculty Publications
Synthetic amorphous silica is a common food additive and a popular cosmetic ingredient. Mesoporous silica particles are also widely studied for their potential use in drug delivery and imaging applications because of their unique properties, such as tunable pore sizes, large surfaces areas, and assumed biocompatibility. Such a nanomaterial, when consisting of pure silicon dioxide, is generally considered to be chemically inert, but in this study, we showed that oxidation yields for different compounds were facilitated by simply incubating aqueous solutions with pure silica particles. Three thiol-containing molecules, L-cysteine, glutathione, and D-penicillamine, were studied separately, and it was found that …
Direct Ink 3d Printing Of Porous Carbon Monoliths For Gas Separations, Marisa L. Comroe, Kurt W. Kolasinski, Dipendu Saha
Direct Ink 3d Printing Of Porous Carbon Monoliths For Gas Separations, Marisa L. Comroe, Kurt W. Kolasinski, Dipendu Saha
Chemistry Faculty Publications
Additive manufacturing or 3D printing is the advanced method of manufacturing monolithic adsorbent materials. Unlike beads or pellets, 3D monolithic adsorbents possess the advantages of widespread structural varieties, low heat and mass transfer resistance, and low channeling of fluids. Despite a large volume of research on 3D printing of adsorbents having been reported, such studies on porous carbons are highly limited. In this work, we have reported direct ink 3D printing of porous carbon; the ink consisted of commercial activated carbon, a gel of poly(4-vinylphenol) and Pluronic F127 as plasticizer, and bentonite as the binder. The 3D printing was performed …
Characterization Of Mechanochemical Modification Of Porous Silicon With Arginine, Jacklyn A. Dipietro, Kurt W. Kolasinski
Characterization Of Mechanochemical Modification Of Porous Silicon With Arginine, Jacklyn A. Dipietro, Kurt W. Kolasinski
Chemistry Faculty Publications
Mechanochemistry initiated the reaction of hydrogen-terminated porous silicon (H/por-Si) powder with arginine. Samples were analyzed using Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. Arginine, which was physisorbed onto the surface of por-Si, blue-shifted the peak PL intensity from similar to 630 nm for the H/por-Si to similar to 565 nm for arginine-coated por-Si. Grinding for 4 h reduced >80% of the initially 2-45 mu m particles to <500 nm, but was observed to quench the PL. With appropriate rinsing and centrifugation, particles in the 100 nm range were isolated. Rinsing ground powder with water was required to remove the unreacted arginine. Without rinsing, excess arginine induced the aggregation of passivated particles. However, water reacted with the freshly ground por-Si powder producing H-2. A zeta potential of +42 mV was measured for arginine-terminated por-Si particles dispersed in deionized water. This positive value was consistent with termination such that NH2 groups extended away from the surface. Furthermore, this result was confirmed by FTIR spectra, which suggested that arginine was bound to silicon through the formation of a covalent Si-O bond.
A Tribute To Professor Gaetano Granozzi And His Contributions To Surface Science On The Occasion Of His 70th Birthday, Kurt W. Kolasinski
A Tribute To Professor Gaetano Granozzi And His Contributions To Surface Science On The Occasion Of His 70th Birthday, Kurt W. Kolasinski
Chemistry Faculty Publications
On the occasion of his 70th birthday, we celebrate the career of our Editor-in-Chief, Professor Gaetano Granozzi. Prof. Granozzi’s work is marked by his dedication to the fundamental understanding of technologically relevant systems through the lens of surface science.
Fabrication Of Electrospun Nanofiber Composite Of G-C3n4 And Au Nanoparticles As Plasmonic Photocatalyst, Dipendu Saha, Pasquale Gismondi, Kurt W. Kolasinski, Samantha L. Shumlas, Sylvie Rangan, Babak Eslami, Amy Mcconnell, Taevaughn Bui, Kayla Cunfer
Fabrication Of Electrospun Nanofiber Composite Of G-C3n4 And Au Nanoparticles As Plasmonic Photocatalyst, Dipendu Saha, Pasquale Gismondi, Kurt W. Kolasinski, Samantha L. Shumlas, Sylvie Rangan, Babak Eslami, Amy Mcconnell, Taevaughn Bui, Kayla Cunfer
Chemistry Faculty Publications
In this research, we have fabricated a composite nanofiber mat of plasmonic photocatalyst consisting of g-C3N4, gold nanoparticles (AuNPs) and random nanofibers of polyvinylidene fluoride (PVDF) by electrospinning. The structure and chemical properties of the nanofiber mat were investigated in detail by ESEM, TEM, AFM, XPS, FTIR, XRD, TGA, PL spectroscopy and UV-Vis reflectance spectra. Imaging of the composite map confirmed that the fiber diameter was in the range of 100-400 nm with the g-C3N4 size in the range of 2-8 μm. Backscattered (Zcontrast) electron imaging in ESEM revealed that the AuNP particle size is in the range of 60-160 …
Metal-Assisted Catalytic Etching (Mace) For Nanofabrication Of Semiconductor Powders, Kurt W. Kolasinski
Metal-Assisted Catalytic Etching (Mace) For Nanofabrication Of Semiconductor Powders, Kurt W. Kolasinski
Chemistry Faculty Publications
Electroless etching of semiconductors has been elevated to an advanced micromachining process by the addition of a structured metal catalyst. Patterning of the catalyst by lithographic techniques facilitated the patterning of crystalline and polycrystalline wafer substrates. Galvanic deposition of metals on semiconductors has a natural tendency to produce nanoparticles rather than flat uniform films. This characteristic makes possible the etching of wafers and particles with arbitrary shape and size. While it has been widely recognized that spontaneous deposition of metal nanoparticles can be used in connection with etching to porosify wafers, it is also possible to produced nanostructured powders. Metal-assisted …
Formulating 3-Chloropropyltriethoxysilane Modified Silica Nanoparticle Sprays As Hydrophobic Transparent Coatings Onto Cotton Textiles, Mikaela C. S. Mendoza, Gilbert U. Yu
Formulating 3-Chloropropyltriethoxysilane Modified Silica Nanoparticle Sprays As Hydrophobic Transparent Coatings Onto Cotton Textiles, Mikaela C. S. Mendoza, Gilbert U. Yu
Chemistry Faculty Publications
Cotton textiles were transformed into hydrophobic fabrics via the application of 3-chloropropylthriethoxysilane-functionalized silica nanoparticle spray coatings. Silica particles were measured to be < 50 nm, as determined by dynamic light scattering (DLS). The incorporation of hexadecyltrimethylammonium bromide (HTAB), a surfactant, into the nanosilica alcohol-based sprays resulted in a suspension that was stable for at least a week. Stability and turbidity tests of samples point to smaller particle size (silica nanoparticles = 24.3 ± 8.5 nm) as the main contributor to possibly providing transparency, as evidenced when sprayed in colored (black) textiles, while still contributing to hydrophobicity/ superhydrophobicity of the cloth.
Soft Ion Sputtering Of Pani Studied By Xps, Afm, Tof-Sims, And Sts, Christopher M. Goodwin, Zachary E. Voras, Xiao Tong, Thomas P. Beebe, Jr.
Soft Ion Sputtering Of Pani Studied By Xps, Afm, Tof-Sims, And Sts, Christopher M. Goodwin, Zachary E. Voras, Xiao Tong, Thomas P. Beebe, Jr.
Chemistry Faculty Publications
Herein is a study of the soft sputtering method, gas cluster ion sputtering (GCIS), and its effects on the atomic, morphologic, and band structure properties of polyaniline (PAni) as studied with X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry, atomic force microscopy, and scanning tunneling spectroscopy (STS). The GCIS source used was a 1000 argon atom cluster with 4 keV energy, which resulted in a sputter yield of 3.4 ± 0.2 × 10−3 nm3 per argon atom. Soft ion sputtering reduced the sample by explicitly removing the oxidized contaminants as determined by surface sensitive techniques: XPS and Time-of-flight secondary …
Low-Load Metal-Assisted Catalytic Etching Produces Scalable Porosity In Si Powders, Konstantin Tamarov, Riku Kiviluoto, Josph D. Swanson, Bret A. Unger, Alexis T. Ernst, Mark Aindow, Joakim Riikonen, Vesa-Pekka Lehto, Kurt W. Kolasinski
Low-Load Metal-Assisted Catalytic Etching Produces Scalable Porosity In Si Powders, Konstantin Tamarov, Riku Kiviluoto, Josph D. Swanson, Bret A. Unger, Alexis T. Ernst, Mark Aindow, Joakim Riikonen, Vesa-Pekka Lehto, Kurt W. Kolasinski
Chemistry Faculty Publications
The recently discovered low-load metal-assisted catalytic etching (LL-MACE) creates nanostructured Si with controllable and variable characteristics that distinguish this technique from the conventional high-load variant. LL-MACE employs 150 times less metal catalyst and produces porous Si instead of Si nanowires. In this work, we demonstrate that some of the features of LL-MACE cannot be explained by the present understanding of MACE. With mechanistic insight derived from extensive experimentation, it is demonstrated that (1) the method allows the use of not only Ag, Pd, Pt, and Au as metal catalysts but also Cu and (2) judicious combinations of process parameters such …
Response Of Photoluminescence Of H-Terminated And Hydrosilylated Porous Si Powders To Rinsing And Temperature, Kurt W. Kolasinski, Joseph D. Swanson, Benjamin Roe, Teresa Lee
Response Of Photoluminescence Of H-Terminated And Hydrosilylated Porous Si Powders To Rinsing And Temperature, Kurt W. Kolasinski, Joseph D. Swanson, Benjamin Roe, Teresa Lee
Chemistry Faculty Publications
The photoluminescence (PL) response of porous Si has potential applications in a number of sensor and bioimaging techniques. However, many questions still remain regarding how to stabilize and enhance the PL signal, as well as how PL responds to environmental factors. Regenerative electroless etching (ReEtching) was used to produce photoluminescent porous Si directly from Si powder. As etched, the material was H-terminated. The intensity and peak wavelength were greatly aected by the rinsing protocol employed. The highest intensity and bluest PL were obtained when dilute HCl(aq) rinsing was followed by pentane wetting and vacuum oven drying. Roughly half of the …
Regenerative Electroless Etching (U.S. Patent), Kurt W. Kolasinski, Jarno Salonen, Ermei Makila
Regenerative Electroless Etching (U.S. Patent), Kurt W. Kolasinski, Jarno Salonen, Ermei Makila
Chemistry Faculty Publications
A regenerative electroless etching process produces nanostructured semiconductors in which an oxidant (Ox 1 ) is used as a catalytic agent to facilitate reaction between a semiconductor and a second oxidant (Ox2) that would be unreactive (or slowly reactive compared to Ox 1 ) in the primary reaction. Ox2 is used to regenerate Ox1 , which can initiate etching by injecting holes into the semiconductor valence band. The extent of reaction is controlled by the amount of Ox2 added; the reaction rate, by the injection rate of Ox2 . This general strategy is demonstrated specifically to produce highly luminescent nanocrystalline …
Fabrication Of A 3d Printed Porous Junction For Ag|Agcl|Gel-Kcl Reference Electrode, Sarah May Sibug-Torres, Lance P. Go, Erwin Enriquez
Fabrication Of A 3d Printed Porous Junction For Ag|Agcl|Gel-Kcl Reference Electrode, Sarah May Sibug-Torres, Lance P. Go, Erwin Enriquez
Chemistry Faculty Publications
Fused filament fabrication (FFF) is a 3D printing method that is attracting increased interest in the development of miniaturized electrochemical sensor systems due to its versatility, low cost, reproducibility, and capability for rapid prototyping. A key component of miniaturized electrochemical systems is the reference electrode (RE). However, reports of the fabrication of a true 3D-printed RE that exhibits stability to variations in the sample matrix remain limited. In this work, we report the development and characterization of a 3D-printed Ag|AgCl|gel-KCl reference electrode (3D-RE). The RE was constructed using a Ag|AgCl wire and agar-KCl layer housed in a watertight 3D-printed acrylonitrile …
Hierarchical Nanostructuring Of Porous Silicon With Electrochemical And Regenerative Electroless Etching, Ermei Mäkilä, Anne-Mari Anton Willmore, Haibo Yu, Marianna Irri, Mark Aindow, Tambet Teesalu, Leigh Trevor Canham, Kurt W. Kolasinski, Jarno Salonen
Hierarchical Nanostructuring Of Porous Silicon With Electrochemical And Regenerative Electroless Etching, Ermei Mäkilä, Anne-Mari Anton Willmore, Haibo Yu, Marianna Irri, Mark Aindow, Tambet Teesalu, Leigh Trevor Canham, Kurt W. Kolasinski, Jarno Salonen
Chemistry Faculty Publications
Hierarchically nanostructured silicon was produced by regenerative electroless etching (ReEtching) of Si powder made from pulverized anodized porous silicon. This material is characterized by ∼15 nm mesopores, into the walls of which tortuous 2–4 nm pores have been introduced. The walls are sufficiently narrow that they support quantum-confined crystallites that are photoluminescent. With suitable parameters, the ReEtching process also provides control over the emission color of the photoluminescence. Ball milling and hydrosilylation of this powder with undecylenic acid produces nanoparticles with hydrodynamic diameter of ∼220 nm that exhibit robust and bright luminescence that can be excited with either one ultraviolet/visible …
Crystallographically Determined Etching And Its Relevance To The Metal-Assisted Catalytic Etching (Mace) Of Silicon Powders, Kurt W. Kolasinski, Bret A. Unger, Alexis T. Ernst, Mark Aindow
Crystallographically Determined Etching And Its Relevance To The Metal-Assisted Catalytic Etching (Mace) Of Silicon Powders, Kurt W. Kolasinski, Bret A. Unger, Alexis T. Ernst, Mark Aindow
Chemistry Faculty Publications
Metal-assisted catalytic etching (MACE) using Ag nanoparticles as catalysts and H2O2 as oxidant has been performed on single-crystal Si wafers, single-crystal electronics grade Si powders, and polycrystalline metallurgical grade Si powders. The temperature dependence of the etch kinetics has been measured over the range 5–37◦C. Etching is found to proceed preferentially in a h001i direction with an activation energy of ∼0.4 eV on substrates with (001), (110), and (111) orientations. A quantitative model to explain the preference for etching in the h001i direction is developed and found to be consistent with the measured activation energies. Etching of metallurgical grade powders …
Photocatalytic Activity: Experimental Features To Report In Heterogeneous Photocatalysis, Md. Ariful Hoque, Marcelo I. Guzman
Photocatalytic Activity: Experimental Features To Report In Heterogeneous Photocatalysis, Md. Ariful Hoque, Marcelo I. Guzman
Chemistry Faculty Publications
Heterogeneous photocatalysis is a prominent area of research with major applications in solar energy conversion, air pollution mitigation, and removal of contaminants from water. A large number of scientific papers related to the photocatalysis field and its environmental applications are published in different journals specializing in materials and nanomaterials. However, many problems exist in the conception of papers by authors unfamiliar with standard characterization methods of photocatalysts as well as with the procedures needed to determine photocatalytic activities based on the determination of “apparent quantum efficiencies” within a wavelength interval or “apparent quantum yields” in the case of using monochromatic …
Hierarchical Porous Silicon And Porous Silicon Nanowires Produced With Regenerative Electroless Etching (Reetching) And Metal Assisted Catalytic Etching (Mace), Kurt W. Kolasinski, Bret A. Unger, Haibo Yu, Alexis T. Ernst, Mark Aindow, Ermei Mäkilä, Jarno Salonen
Hierarchical Porous Silicon And Porous Silicon Nanowires Produced With Regenerative Electroless Etching (Reetching) And Metal Assisted Catalytic Etching (Mace), Kurt W. Kolasinski, Bret A. Unger, Haibo Yu, Alexis T. Ernst, Mark Aindow, Ermei Mäkilä, Jarno Salonen
Chemistry Faculty Publications
ReEtching produces nanostructured silicon when a catalytic agent, e.g. dissolved V2O5, is used to facilitate etching between Si and H2O2. H2O2 regenerates dissolved V in a 5+ oxidation state, which initiates etching by injecting holes into the Si valence band. Independent control over the extent of reaction (controlled by the amount of H2O2 added) and the rate of reaction (controlled by the rate at which H2O2 is pumped into the etchant solution) allows us to porosify Si substrates of arbitrary size, shape and doping, including wafers, single-crystal powders, polycrystalline powders, metallurgical grade powder, Si nanowires, Si pillars and Si powders …
Crystallographically Defined Silicon Macropore Membranes, Shannon C. Knight, Bret A. Unger, Kurt W. Kolasinski
Crystallographically Defined Silicon Macropore Membranes, Shannon C. Knight, Bret A. Unger, Kurt W. Kolasinski
Chemistry Faculty Publications
Laser ablation with nanosecond-pulsed Nd:YAG laser irradiation combined with anisotropic alkaline etching of Si wafers creates 4–20 µm macropores that extend all the way through the wafer. The walls of these macropores are crystallographically defined by the interaction of the anisotropy of the etchant with the orientation of the single-crystal silicon substrate: rectangular/octagonal on Si(001), parallelepiped on Si(110), triangular/hexagonal on Si(111). Laser ablation can create pillars with peak-tovalley heights of over 100 µm. However, with nanosecondpulsed irradiation at 532 nm, the majority of this height is created by growth above the original plane of the substrate whereas for 355 nm …
Silicon Surface Photochemistry, Kurt W. Kolasinski
Silicon Surface Photochemistry, Kurt W. Kolasinski
Chemistry Faculty Publications
General concepts of photochemistry on metal and semiconductor surfaces are elucidated. These concepts are then applied more specifically to describe photochemical transformation of molecules on and with silicon surfaces. The mechanisms by which light can induce chemical reactions following electronic excitation are described. Processes reviewed include photodissociation of adsorbed molecules, photo-induced attachment of organic molecules and photo-induced corrosion.
Plume And Nanoparticle Formation During Laser Ablation, Kurt W. Kolasinski, Mool C. Gupta, Leonid V. Zhigilei
Plume And Nanoparticle Formation During Laser Ablation, Kurt W. Kolasinski, Mool C. Gupta, Leonid V. Zhigilei
Chemistry Faculty Publications
The processes that lead to material ejection when a solid sample is irradiated near and above the pulsed laser ablation threshold are discussed. Emphasis is placed on the thermal and mechanical mechanisms that occur during pulsed laser irradiation of metals and semiconductors. Distinctions are drawn between ultrafast-pulsed irradiation, which occurs under stress confinement, and shortpulsed irradiation, in which stress is released during the laser pulse. Similarly, the distinctions between the spallation and phase explosion regimes are discussed. Spallation is only possible when the time of the laser heating is shorter than the time needed for mechanical equilibration of the heated …
Differentiating The Impact Of Nitrogen Chemical States On Optical Properties Of Nitrogen-Doped Graphene Quantum Dots, Timothy Pillar-Little, Doo Young Kim
Differentiating The Impact Of Nitrogen Chemical States On Optical Properties Of Nitrogen-Doped Graphene Quantum Dots, Timothy Pillar-Little, Doo Young Kim
Chemistry Faculty Publications
The optical properties of top-down synthesized oxidized graphene quantum dots (ox-GQDs) and nitrogen-incorporating graphene quantum dots (N-GQDs) along a range of hydrothermal treatment temperatures were observed. By controlling the hydrothermal treatment temperature, different chemical states of nitrogen atoms were incorporated into GQDs. Below 150 °C, edge-terminating amines and amides dominated the nitrogen content of N-GQDs. Above 150 °C, nitrogen was primarily present in the forms of pyridinic, pyrrolic and quaternary N. In addition to the absorbance and emission profiles of ox-GQDs and N-GQDs, pH-dependent emission spectra were collected to probe chemical states of nitrogen atoms and investigate the relationship between …
Regioselective Baeyer–Villiger Oxidation Of Lignin Model Compounds With Tin Beta Zeolite Catalyst And Hydrogen Peroxide, John Adam Jennings, Sean R. Parkin, Eric Munson, Sean Delaney, Julie L. Calahan, Mark Isaacs, Kunlun Hong, Mark Crocker
Regioselective Baeyer–Villiger Oxidation Of Lignin Model Compounds With Tin Beta Zeolite Catalyst And Hydrogen Peroxide, John Adam Jennings, Sean R. Parkin, Eric Munson, Sean Delaney, Julie L. Calahan, Mark Isaacs, Kunlun Hong, Mark Crocker
Chemistry Faculty Publications
Lignin depolymerization represents a promising approach to the sustainable production of aromatic molecules. One potential approach to the stepwise depolymerization of lignin involves oxidation of the benzylic alcohol group in β-O-4 and β-1 linkages, followed by Baeyer–Villiger oxidation (BVO) of the resulting ketones and subsequent ester hydrolysis. Towards this goal, BVO reactions were performed on 2-adamantanone, a series of acetophenone derivatives, and lignin model compounds using a tin beta zeolite/hydrogen peroxide biphasic system. XRD, 119Sn MAS NMR spectroscopy, DRUVS and XPS were used to determine tin speciation in the catalyst, the presence of both framework Sn and extra framework …
Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Marcelo I. Guzman, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali
Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Marcelo I. Guzman, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali
Chemistry Faculty Publications
How primordial metabolic networks such as the reverse tricarboxylic acid (rTCA) cycle and clay mineral catalysts coevolved remains a mystery in the puzzle to understand the origin of life. While prebiotic reactions from the rTCA cycle were accomplished via photochemistry on semiconductor minerals, the synthesis of clays was demonstrated at low temperature and ambient pressure catalyzed by oxalate. Herein, the crystallization of clay minerals is catalyzed by succinate, an example of a photoproduced intermediate from central metabolism. The experiments connect the synthesis of sauconite, a model for clay minerals, to prebiotic photochemistry. We report the temperature, pH, and concentration dependence …
Controlled Microfabrication Of High-Aspect-Ratio Structures In Silicon At The Highest Etching Rates: The Role Of H2o2 In The Anodic Dissolution Of Silicon In Acidic Electrolytes, Chiara Cozzi, Giovanni Polito, Kurt W. Kolasinski, Giuseppe Barillaro
Controlled Microfabrication Of High-Aspect-Ratio Structures In Silicon At The Highest Etching Rates: The Role Of H2o2 In The Anodic Dissolution Of Silicon In Acidic Electrolytes, Chiara Cozzi, Giovanni Polito, Kurt W. Kolasinski, Giuseppe Barillaro
Chemistry Faculty Publications
In this work the authors report on the controlled electrochemical etching of high-aspect-ratio (from 5 to 100) structures in silicon at the highest etching rates (from 3 to 10 µm min−1) at room temperature. This allows silicon microfabrication entering a previously unattainable region where etching of high-aspect-ratio structures (beyond 10) at high etching rate (over 3 µm min−1) was prohibited for both commercial and research technologies. Addition of an oxidant, namely H2O2, to a standard aqueous hydrofluoric (HF) acid electrolyte is used to dramatically change the stoichiometry of the silicon dissolution process under anodic biasing without loss of etching control …
Regenerative Electroless Etching Of Silicon, Kurt W. Kolasinski, Nathan J. Gimbar, Haibo Yu, Mark Aindow, Ermei Mäkilä, Jarno Salonen
Regenerative Electroless Etching Of Silicon, Kurt W. Kolasinski, Nathan J. Gimbar, Haibo Yu, Mark Aindow, Ermei Mäkilä, Jarno Salonen
Chemistry Faculty Publications
Regenerative electroless etching (ReEtching), described herein for the first time, is a method of producing nanostructured semiconductors in which an oxidant (Ox1) is used as a catalytic agent to facilitate the reaction between a semiconductor and a second oxidant (Ox2) that would be unreactive in the primary reaction. Ox2 is used to regenerate Ox1, which is capable of initiating etching by injecting holes into the semiconductor valence band. Therefore, the extent of reaction is controlled by the amount of Ox2 added, and the rate of reaction is controlled by the injection rate of Ox2. This general strategy is demonstrated specifically …
Charge Transfer At The Liquid/Solid Interface To Affect Nanostructure Formation, Kurt W. Kolasinski
Charge Transfer At The Liquid/Solid Interface To Affect Nanostructure Formation, Kurt W. Kolasinski
Chemistry Faculty Publications
No abstract provided.
Subtractive Methods To Form Pyrite And Sulfide Nanostructures Of Fe, Co, Ni, Cu And Zn, Kurt W. Kolasinski
Subtractive Methods To Form Pyrite And Sulfide Nanostructures Of Fe, Co, Ni, Cu And Zn, Kurt W. Kolasinski
Chemistry Faculty Publications
The low Z metals Fe, Co, Ni, Cu and Zn are Earth abundant, i.e. inexpensive, and their sulfides are of low toxicity. This makes them appealing candidates for materials applications requiring semiconductors or, in the case of CoS2, a metal since they can potentially be produced in large quantities and low cost. Though of great potential little work has explored how subtractive methods can be used to form nanostructured and/or porous structures in, e.g. FeS2, CoS2, NiS, Cu2S and ZnS.
Relating Side Chain Organization Of Pnipam With Its Conformation In Aqueous Methanol, Debashish Mukherji, Manfred Wagner, Mark D. Watson, Svenja Winzen, Tiago E. E. De Oliveira, Carlos M. Marques, Kurt Kremer
Relating Side Chain Organization Of Pnipam With Its Conformation In Aqueous Methanol, Debashish Mukherji, Manfred Wagner, Mark D. Watson, Svenja Winzen, Tiago E. E. De Oliveira, Carlos M. Marques, Kurt Kremer
Chemistry Faculty Publications
Combining nuclear magnetic resonance (NMR), dynamic light scattering (DLS), and μs long all-atom simulations with two million particles, we establish a delicate correlation between increased side chain organization of PNIPAm and its collapse in aqueous methanol mixtures. We find that the preferential binding of methanol with PNIPAm side chains, bridging distal monomers along the polymer backbone, results in increased organization. Furthermore, methanol–PNIPAm preferential binding is dominated by hydrogen bonding. Our findings reveal that the collapse of PNIPAm is dominated by enthalpic interactions and that the standard poor solvent (entropic) effects play no major role.
To Bend Or Not To Bend – Are Heteroatom Interactions Within Conjugated Molecules Effective In Dictating Conformation And Planarity?, Gary Conboy, Howard J. Spencer, Enrico Angioni, Alexander L. Kanibolotsky, Neil J. Findlay, Simon J. Coles, Claire Wilson, Mateusz B. Pitak, Chad Risko, Veaceslav Coropceanu, Jean-Luc Brédas, Peter J. Skabara
To Bend Or Not To Bend – Are Heteroatom Interactions Within Conjugated Molecules Effective In Dictating Conformation And Planarity?, Gary Conboy, Howard J. Spencer, Enrico Angioni, Alexander L. Kanibolotsky, Neil J. Findlay, Simon J. Coles, Claire Wilson, Mateusz B. Pitak, Chad Risko, Veaceslav Coropceanu, Jean-Luc Brédas, Peter J. Skabara
Chemistry Faculty Publications
We consider the roles of heteroatoms (mainly nitrogen, the halogens and the chalcogens) in dictating the conformation of linear conjugated molecules and polymers through non-covalent intramolecular interactions. Whilst hydrogen bonding is a competitive and sometimes more influential interaction, we provide unambiguous evidence that heteroatoms are able to determine the conformation of such materials with reasonable predictability.
Electron Transfer During Metal-Assisted And Stain Etching Of Silicon, Kurt W. Kolasinski
Electron Transfer During Metal-Assisted And Stain Etching Of Silicon, Kurt W. Kolasinski
Chemistry Faculty Publications
The etching of silicon in fluoride solutions is limited by the kinetics of charge transfer not thermodynamics. This characteristic is what gives fluoride etching its great versatility in making different types of nanostructures as the result of self-limiting chemistry. This review approaches the kinetics of electron transfer from silicon and metal coated silicon to a solution phase species from a fundamental point of view in order to establish a better understanding of the mechanisms of nanostructure formation during metal assisted and stain etching of silicon. Band bending calculations demonstrate that diffusion of holes away from low work function metals such …
Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert
Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert
Chemistry Faculty Publications
Several potential new phosphorus-containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3-propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability testing …