Chemistry Commons^™

Research And Application Of Copper Electroplating In Interconnection Of Printed Circuit Board, Chong Wang, Chuan Peng, Jing Xiang, Yuan-Ming Chen, Wei He, Xin-Hong Su, Yu-Yao Luo

Journal of Electrochemistry

Copper electroplating is the key technology for manufacturing of integrated circuit, packaging substrate, printed circuit board, and other electronic interconnection components. However, the electrochemistry and mechanism of deposition growth have not been fully elucidated, and the development of additives and bath maintenance are inseparable from a large number of experiments. This article reviews recent fundamental research and application progress in copper electroplating for printed circuit board industry, and these works are mainly dedicated by the research group of Printed Circuit and Printed Electronics from University of Electronic Science and Technology of China. First of all, a brief history of copper …

Synthesis And Electrochemical Study Of Cuau Nanodendrites For Co2 Reduction, Dylan Siltamaki, Shuai Chen, Farnood Rahmati, Jacek Lipkowski, Ai-Cheng Chen

Journal of Electrochemistry

The conversion of carbon dioxide (CO₂) to carbon monoxide (CO) and other value-added products is an interesting approach for carbon-containing fuel synthesis using renewable and clean energy. The electrochemical reduction of CO₂ is one of the promising strategies for the storage of intermittent renewable energy resources. The development of electrocatalysts with high activity and stability is vital in the electrochemical CO₂ reduction process. In this study, copper and gold alloyed (CuAu) electrodes with nanodendritic structures were synthesized using a facile electrodeposition method. The CuAu nanodendrites with the atomic ratio of Cu to Au being approximately 1:1 …

Recent Advances In Glycerol Electrooxidation On Pt And Pd: From Reaction Mechanisms To Catalytic Materials, Wei-Yi Zhang, Xian-Yin Ma, Shou-Zhong Zou, Wen-Bin Cai

Journal of Electrochemistry

The conversion of glycerol to value-added products has received considerable attention recently because the booming biodiesel industry produces a large amount of glycerol as a byproduct. Among various means, electrocatalytic oxidation of glycerol is appealing owing to its environmental friendliness and high efficiency. However, electrooxidation of glycerol is very complex, involving multiple electron and proton transfer processes with many reaction pathways. How to rationally design catalysts with high selectivity toward targeted products is an overarching challenge, and of both fundamental and practical significance. In this minireview we aim to provide an overview of recent advancements in electrooxidation of glycerol focusing …

Progress Of Lithium-Ion Transport Mechanism In Solid-State Electrolytes, Bing-Kai Zhang, Lu-Yi Yang, Shun-Ning Li, Feng Pan

Journal of Electrochemistry

Inorganic crystalline solid electrolytes exhibit exceptional room-temperature ionic conductivities, giving them the potential to enable all-solid-state lithium (Li) - ion batteries. Developing new high-performance electrolytes is one of the most critical challenges to realize solid-state batteries, which requires understanding how chemistry facilitates fast ionic conduction and what the Li-ion migration mechanism is in inorganic solid electrolytes. In this review, we aim to summarize recent fundamental research progress in Li-ion transport, including crystal structure, behavior of ion migration (i.e., single-ion jump and multi-ions cooperative migration), and the relationship between ion migration and microstructure.
Generally, ion transport in crystalline structure can be …

Studies And Progresses On Hole Metallization In High-Density Interconnected Printed Circuit Boards, Zhao-Yun Wang, Lei Jin, Jia-Qiang Yang, Wei-Qing Li, Dong-Ping Zhan, Fang-Zu Yang, Shi-Gang Sun

Journal of Electrochemistry

Printed circuit boards (PCBs) are almost the core components of all electronic systems. With the rapid development of sciences and technologies, PCBs are gradually developing in the direction of multi-layer, thin and high-density wiring due to the functionalization, miniaturization, lightweight and high reliability of electronic products, as well as the widespread popularization of the subminiature package such as chip scale package (CSP) and ball grid array (BGA). Therefore, High-density interconnected printed circuit boards (HDI-PCBs) arise. Hole metallization is one of the core technologies in HDI-PCBs and includes two processes composed of conductive treatment and electron electroplating. Electroless copper plating, as …

Design And Fabrication Of The Electrolytic Cell With Silicon-Based Boron-Doped Diamond Electrode And Its Feasibility ForIn-Situ Nuclear Magnetic Resonance Study, Hao Peng, Hui-Jun Sun, Zhi-You Zhou, Lin-Fan Shen, Long Huang, Shuo-Hui Cao, Shi-Gang Sun

Journal of Electrochemistry

In-situ EC-NMR technique can be used to monitor the electrochemical reaction process in real-time and to explain the reaction mechanism at the molecular level, which is a promising and non-destructive online detection technology. This article for the first time reports the design and production of in-situEC-NMR three-electrode single-chamber electrolytic cell using silicon-based boron-doped diamond (Si/BDD) as the working electrode. Research shows that the geometric size of Si/BDD electrode being 12.5 mm 1.2 mm 0.5 mm in the NMR detection zone is small and the thickness of the electrode material is thin, which accounts for the less hindrance …

Mathematical Model For Measuring The Concentration Of Nanoparticles In A Liquid During Sedimentation, Safaa Mohammed Ridha Hussien Hussien, Airat Sakhabutdinov, Vladimir Anfinogentov, Maxim Danilaev, Vladimir Kuklin, Oleg Morozov

Karbala International Journal of Modern Science

Expanding the application areas of polymer composite materials with dispersed filler requires the development of technologies providing the required mechanical characteristics. One of these methods is based on forming a thin polymer shell on the surfaces of particles. At the same time, it is impossible to take into account the mechanical characteristics of a thin polymer shell due to its ultra-small thickness. The mechanical properties of the polymer shell can be determined only by indirect methods, and prior information can improve the adequacy of the properties determination. The method, which allows reducing the requirements for composite sample preparation, is proposed. …

Investigations Into Size And Surface Control Of Silicon Nanocrystals For Improved Optical Properties, James Donald Barnes

Dissertations and Theses

The discovery of visible photoluminescence (PL) from nanocrystalline porous silicon in 1990 led to extensive research into the mechanisms of the emergent properties, and optimization of these properties, for use in applications. The widespread use of silicon nanoparticles (Si NPs) in commercial applications is currently limited by three main factors: 1) poor radiative recombination efficiency of the interband transition, 2) instability of the interband photoluminescence, and 3) a lack of scalable methods for producing Si NPs that are both highly crystalline and size monodisperse.

To address these limitations, this dissertation correlates changes in the photoluminescence properties of hydrogen passivated silicon …

Quantum Transport Of The 2d Surface State In A Nonsymmorphic Semimetal, Xue Liu, Jin Hu, Jiang Wei, Chunlei Yue, Sergey V. Erohin, Yanglin Zhu, Abin Joshy, Jinyu Liu, Ana M. Sanchez, David Graf, Pavel B. Sorokin, Zinqiang Mao

Physics Faculty Publications and Presentations

In a topological semimetal with Dirac or Weyl points, the bulk-boundary correspondence principle predicts a gapless edge mode if the essential symmetry is still preserved at the surface. The detection of such topological surface state has been considered as the fingerprint prove for crystals with nontrivial topological bulk band. On the contrary, it has been proposed that even with symmetry broken at the surface, a new surface band can emerge in nonsymmorphic topological semimetals. The symmetry reduction at the surface lifts the bulk band degeneracies and produces an unusual “floating” surface band with trivial topology. Here, we first report quantum …

Pressure Driven Desalination Membranes: Lyotropic Liquid Crystals Containing Single Walled Carbon, Matteo A. Del Giudice, Samantha Castillo Merigold

Materials Engineering

This project presents a potential alternative desalination technique that utilizes the ion rejection properties of single walled carbon nanotubes dispersed in a lyotropic liquid crystal (LLC) matrix. Previous research has pointed to the polymerizable surfactant methacryloxy ethyl hexadecyl dimethyl ammonium bromide (C16MA) having capabilities of filtering molecular components smaller than a nanometer, when oriented in cylindrical micelles. SWCNTs were dispersed in deionized water by probe sonication and addition of surfactant cetyltrimethylammonium bromide (CTAB) due to SWCNTs’ hydrophobic properties. Membranes were produced containing 55wt% C16MA, 37wt% DI water, 0.1wt% with respect to the monomer (WRM) SWCNTs, 1.9 wt% WRM 2,2-dimethoxy-2-phenylacetophenone (photointiator), …

High Performance Mixed-Matrix Electrospun Membranes For Ammonium Removal From Wastewaters, Shu-Ting Chen, Sumith Ranil Wickramasinghe, Xianghong Qian

Chemical Engineering Faculty Publications and Presentations

Mixed-matrix electrospun membranes were developed to investigate ammonium removal from low ammonium concentration wastewaters for the first time. Particles derived from the inexpensive zeolite 13X were successfully incorporated into polyethersulfone (PES) matrices. The fabricated mixed-matrix electrospun membranes demonstrate high ammonium removal capacity reaching over 55 mg/g_zeolite, more than 2.5 times higher than the previously fabricated mixed-matrix membranes via non-solvent induced phase inversion. Moreover, the membranes fabricated exhibit high permeability and ease of regeneration. Over 90% of total ammonium nitrogen (TAN) can be removed from low TAN wastewaters such as aquaculture wastewaters. In addition to zeolite 13X, other zeolite …

Effects Of Air Pollution, Temperature And Moisture Content On Copper And Silver Corrosions And The Reliability Of Data Center Equipment, Rui Zhang

Dissertations - ALL

The effects of moisture content, temperature, and pollutant mixture on atmospheric corrosion of copper and silver were investigated by exposing test specimens to different environmental conditions, followed by surface characterization using the coulometric reduction, Scanning Electron Microscopy, and Energy Dispersive Spectrometry (SEM/EDS). Printed circuit board test cards (PCBs) with bare copper were also used to investigate the effects of voltage bias on the PCBs on the corrosion rate. The test specimens were exposed to mixed flowing gases (MFG) environment with eight different combinations of the following five pollutants at the fixed concentration levels: 60 ppb O3, 80 ppb NO2, 40 …

Computational Algorithms For Predicting Membrane Protein Assembly From Angstrom To Micron Scale, Nandhini Rajagopal

Dissertations - ALL

Biological barriers in the human body are one of the most crucial interfaces perfected through evolution for diverse and unique functions. Of the wide range of barriers, the paracellular protein interfaces of epithelial and endothelial cells called tight junctions with high molecular specificities are vital for homeostasis and to maintain proper health. While the breakdown of these barriers is associated with serious pathological consequences, their intact presence also poses a challenge to effective delivery of therapeutic drugs. Complimenting a rigorous combination of in vitro and in vivo approaches to establishing the fundamental biological construct, in addition to elucidating pathological implications …

Effects Of Air Pollution, Temperature And Moisture Content On Copper And Silver Corrosions And The Reliability Of Data Center Equipment, Rui Zhang

Dissertations - ALL

The effects of moisture content, temperature, and pollutant mixture on atmospheric corrosion of copper and silver were investigated by exposing test specimens to different environmental conditions, followed by surface characterization using the coulometric reduction, Scanning Electron Microscopy, and Energy Dispersive Spectrometry (SEM/EDS). Printed circuit board test cards (PCBs) with bare copper were also used to investigate the effects of voltage bias on the PCBs on the corrosion rate. The test specimens were exposed to mixed flowing gases (MFG) environment with eight different combinations of the following five pollutants at the fixed concentration levels: 60 ppb O3, 80 ppb NO2, 40 …

Aerosol Vapor Synthesis Of Organic Processable Pedot Particles And Measuring Electric Conductivity Using A 3d Printed Probe Station, Yang Lu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Conducting polymers are organic semiconductors characterized by conjugated backbones (alternating single-double bonds) that enable mixed ionic-electronic conductivity. Their polymeric nature, tunable band structure and reversible redox capability have demonstrated fundamental advances in the fields ranging from electrochemical energy storage, sensing, to electro/photo catalysis and neuromorphic engineering. Conjugated backbones, the origin of all the unique physical and chemical properties associated with conducting polymers, prevent their solubility due to high lattice energy which hinders processing. Current solution utilizes a long-chain polymer (PSS) as dopants to render conducting polymer water dispersible (PEDOT:PSS). Nonetheless, PSS is highly acidic and hydrophilic limiting applicability with acid-incompatible …

Atomic Oxygen Resistant Low Earth Orbit Stable Polymer Matrix Composites Employing Phenylphosphine Oxide Epoxy-Amines, Witold Fuchs

Dissertations

Atomic oxygen (AO) attacks polymer matrix composites (PMC’s) on the surfaces of spacecraft in low earth orbit (LEO) and threatens safe spacecraft operation and service life. Incorporating phenylphosphine oxide (PPO) groups into polymer chains offers a self-regenerating method of protection from AO but remains poorly understood. Herein, epoxies containing PPO groups were synthesized with increasing concentrations of phosphorus [P] from 0 to 8 wt % to investigate their AO resistance. Measurements confirmed the exposure of these materials to AO produces a passivation phosphate (POx) layer on the surface of the sample and the efficacy of the resultant layer was directly …

Post Covid-19 Water And Waste Water Management To Protect Public Health And Geoenvironment, Ken Cornell, Arvin Farid

Chemistry and Biochemistry Faculty Publications and Presentations

The coronavirus disease 2019 pandemic has posed severe threats to humans and the geoenvironment. The findings of severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) traces in waste water and the practice of disinfecting outdoor spaces in several cities in the world, which can result into the entry of disinfectants and their by-products into storm drainage systems and their subsequent discharge into rivers and coastal waters, raise the issue of environmental, ecological and public health effects. The aims of the current paper are to investigate the potential of water and waste water to operate as transmission routes for Sars-CoV-2 and the …

Synthesis And Characterization Of Functiona Materials For 3d Printed Composites, Elizabeth Irene Reza

Open Access Theses & Dissertations

The following body of work encompasses the synThesis, upscaling, additive manufacturing, and characterization of microspheres as functional fillers incorporated into polymer syntactic foams. Synthesizing microspheres permits control over morphology, dispersion of particles, and size while the use of direct write manufacturing allowed for the controllability of filler orientation. Two different syntactic foams were developed from similar methodologies: (1) a silicone syntactic foam (2) epoxy syntactic foam. The silicone epoxy foam showed an increasing in damping and elastic modulus. The epoxy syntactic foams showed an enhanced thermal and electrical properties.

Development Of Biomaterials For Drug Delivery, Raquel De Castro

Graduate Theses and Dissertations

Drug delivery systems (DDS) have highly evolved in the last decades with the development of hydrogels and nanoparticles. However, high systemic uptake, side effects, low bioavailability, and encapsulation efficiency continue to be a major hurdle faced by such DDSs.

Nanoparticles and hydrogels can be specifically designed for targeted DDSs to mitigate some of the problems. This dissertation aimed to design two DDSs for ocular drug delivery and one for cancer treatment. The first project sought to develop chitosan nanoparticles (Cs-NP) using PEGDA as a copolymer to encapsulate gentamicin (GtS) for ocular drug delivery. Cs-NPs contain positive charges that can interact …

Photothermal Response Induced By Nanocage-Coated Artificial Extracellular Matrix Promotes Neural Stem Cell Differentiation, Seunghyun Jung, Nathaniel Harris, Isabelle I. Niyonshuti, Samir V. Jenkins, Abdallah M. Hayar, Fumiya Watanabe, Azemat Jamshidi-Parsian, Jingyi Chen, Michael J. Borrelli, Robert J. Griffin

Mechanical Engineering Faculty Publications and Presentations

Strategies to increase the proportion of neural stem cells that differentiate into neurons are vital for therapy of neurodegenerative disorders. In vitro, the extracellular matrix composition and topography have been found to be important factors in stem cell differentiation. We have developed a novel artificial extracellular matrix (aECM) formed by attaching gold nanocages (AuNCs) to glass coverslips. After culturing rat neural stem cells (rNSCs) on these gold nanocage-coated surfaces (AuNC-aECMs), we observed that 44.6% of rNSCs differentiated into neurons compared to only 27.9% for cells grown on laminin-coated glass coverslips. We applied laser irradiation to the AuNC-aECMs to introduce precise …

Remote Performance Modulation Of Ultrafiltration Membranes By Magnetically And Thermally Responsive Polymer Chains, Arijit Sengupta, Anh Vu, Xianghong Qian, Sumith R. Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

Ultrafiltration membranes, that respond to an external magnetic field and local temperature have been developed. Surface-initiated activator-generated electron transfer (AGET) atom transfer radical polymerization (ATRP) has been used to graft poly(N-isopropylacrylamide) (PNIPAm) from the surface of 300 kDa regenerated cellulose membranes. The polymerization initiator was selectively attached to the entire membrane surface, only the outer membrane surface or only the inner pore surface. A superparamagnetic nanoparticle was attached to the end of the polymer chain. The DI water flux as well as the flux and rejection of bovine serum albumin were investigated in the absence and presence of a 20 …

Biomedical Applications And Syntheses Of Selected Anthraquinone Dyes, Richard Sirard

Senior Honors Theses

Anthraquinones are aromatic organic compounds that have multiple applications in the biomedical field. Some anthraquinone-based compounds are used as fluorophores to contrast cell nuclei while others act as chemotherapeutic agents. However, there are not many fluorescent anthraquinone cell stains currently available. In this study, commercially available anthraquinone dyes, in addition to other dye families and compounds, were reviewed for their unique properties, advantages, and drawbacks. The development and characterization of three novel anthraquinone fluorophores revealed promising photophysical characteristics, like large Stokes shifts. One of the compounds, RBS3, was chosen for fixed and live cell staining and exhibited desirable biomedical properties. …

Preparation And Characterization Of "Water-In-Salt" Polymer Electrolyte For Lithium-Ion Batteries, Xu Hou, Xin He, Jie Li

Journal of Electrochemistry

Since the development of wearable and flexible electronic products, the demand of flexible energy storage devices such as batteries and super capacitors is in urgent. To enhance the safety and cycling stability for flexible lithium-ion batteries, “water-in-salt” polymer electrolyte was prepared by introducing 21 mol·kg^-1 LiTFSI electrolyte into cross-linked polyacrylamide (PAM) after freeze-drying. A great amount of holes with the size range of 10 ~ 20 μm can be found on the surface and in the bulk of polyacrylamide, which is benefited from the freeze-drying process and acts as a great support for the electrolyte uptake. The “water-in-salt” polymer …

Application Of Atomically Precise Metal Nanoclusters In Electrocatalysis, Zhi-Hua Zhuang, Wei Chen

Journal of Electrochemistry

Metal nanoclusters (M NCs) consist of only several to a few hundred of metal atoms and possess core sizes less than 2 nm. Owing to the quantum size effect, the electronic states of M NCs evolve to discrete levels similar to the molecule energy gaps, other than a continuous density of states to produce plasmon characteristic of bulk metal nanoparticles (M NPs). In comparison with the conventional M NPs, M NCs exhibit dramatically unique electronic and optical properties, such as molecule-like energy gaps, strong photoluminescence and high catalytic properties, which make them promising for potential application in numerous fields, such …

Electrochemiluminescence Imaging Hydrogen Evolution Reaction On Single Platinum Nanoparticles Using A Bipolar Nanoelectrode Array, Xiang Qin, Zhong-Qiu Li, Jian-Bin Pan, Jian Li, Kang Wang, Xing-Hua Xia

Journal of Electrochemistry

A high-density (5.7 × 10⁸ cm^-2) nanoelectrode array with the electrode diameter of 200 nm and the interelectrode distance of 450 nm were fabricated. The nanoelectrode array consisted of gold nanowires embedded in a porous anodic aluminum oxide (AAO) matrix, having regular nanoelectrode distribution and highly uniform nanoelectrode size. The gold nanoelectrode array was used as a closed bipolar nanoelectrode array combined with electrochemiluminescence (ECL) method to map the electrocatalytic activity of platinum nanoparticles toward hydrogen evolution reaction (HER) by modifying the catalysts on single nanoelectrodes. Results show that HER on single bipolar nanoelectrodes could be imaged …

Oxygen-Exposure Induced Rapid Oxidation Of Spiro-Ometad In Cspbibr2 Perovskite Solar Cells, Wei-Guo Wang, Tian Bai, Gao-Fei Xue, Mei-Dan Ye

Journal of Electrochemistry

2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (Spiro-OMeTAD) is the most widely used hole transport material in perovskite solar cells (PSCs). However, its oxidation in the air takes a long time and results in the attack of perovskite by water. In this regard, we performed the oxidation process of Spiro-OMeTAD in oxygen, where perovskite can be protected from water, guaranteeing the integrity of perovskite. It was demonstrated that the champion Spiro-OMeTAD based CsPbIBr₂ PSCs after oxygen oxidation achieved a 7.19% power conversion efficiency (PCE), showing a higher PCE than 6.29% of the champion device oxidized in air. A series of electrochemical characterization methods were applied …

Theoretical Studies Of Metal-N-C For Oxygen Reduction And Hydrogen Evolution Reactions In Acid And Alkaline Solutions, Xue-Ping Qin, Shang-Qian Zhu, Lu-Lu Zhang, Shu-Hui Sun, Min-Hua Shao

Journal of Electrochemistry

Single atom catalysts (SAC) have been regarded as the promising alternatives to platinum group metals due to their low costs and potentially high catalytic activities in various electrocatalytic reactions. The atomic mechanism understanding of activity discrepancy among different metal and nitrogen co-doped carbon-based catalysts is still lacking. Here, non-precious metal and nitrogen co-doped carbons (Me-N-C, Me = Fe and Co) as the model catalysts are investigated by combining experimental and theoretical studies to explore the catalytic activities and corresponding reaction mechanisms toward oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) at universal pHs. Atomic theoretical simulations suggest that Fe-N-C …

Electrochemical Surface-Enhanced Raman Spectroscopic Studies On Nickel Ultramicroelectrode, Li-Wen Wu, Wei Wang, Yi-Fan Huang

Journal of Electrochemistry

Nickel (Ni) electrodes are widely used in electrochemical researches. Understanding electrochemical processes on Ni electrodes through in-situ characterization of adsorbed species on their surfaces is helpful for rational optimization and application of Ni electrochemistry. Microelectrochemical surface-enhanced Raman spectroscopy (μEC-SERS) combines the mass transfer feature of ultramicroelectrode with high-sensitivity characterizations of molecular structures, which is a powerful method for studying Ni electrochemistry on polarization and non-equilibrium conditions. The key point of performing μEC-SERS is to make a SERS-active Ni ultramicroelectrode.
Here, we demonstrate a method of preparing a SERS-active Ni ultramicroelectrode through electrochemical deposition of several atomic layers of …

Electrochemical Gating Single-Molecule Circuits With Parallel Paths, Jun-Qing Su, Yi-Fan Zhou, Ling Tong, Ya-Hao Wang, Ju-Fang Zheng, Jing-Zhe Chen, Xiao-Shun Zhou

Journal of Electrochemistry

Electrochemical gating has emerged as a feasible and powerful method to tune single-molecule conductance. Herein, we demonstrate that the electron transport through single-molecule circuits with two benzene rings in parallel could be efficiently gated by electrochemistry. The molecular junctions with two parallel paths are fabricated with Au electrodes by STM break junction (STM-BJ) technique. Their conductance value exhibits a 2.82-fold enhancement by the constructive quantum interference compared to single-molecule junctions with single path for electron tunneling. Furthermore, the conductance of para-benzene based molecule could be electrochemically tuned with a modulation ratio of about 333%·V^-1. With the help of …

Lithium Storage Performance Of Hard Carbons Anode Materials Prepared By Different Precursors, Zhen-Lang Liang, Yao Yang, Hao Li, Li-Ying Liu, Zhi-Cong Shi

Journal of Electrochemistry

Hard carbon is one of the most promising anode material for lithium ion batteries (LIBs) owing to its high stability, widespread availability, low-cost, and excellent performance. The electrochemical properties of hard carbon materials depend strongly on the type of precursors. It is, therefore, very important to choose an excellent hard carbon precursor. Polyacrylonitrile, petroleum pitch and peanut shells were used as raw materials to prepare different hard carbon anode materials for LIBs. These hard carbon anode materials were successfully synthesized in two steps. The selected precursor was firstly carbonized at 600℃ for 1 h in argon atmosphere using heating rate …