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Articles 1 - 14 of 14

Full-Text Articles in Other Engineering

Halogen-Free Ultra-High Flame Retardant Polymers Through Enzyme Catalysis, Sethumadhavan Ravichandran, Subhalakshmi Nagarajan, Bon Choel Ku, Bryan Coughlin, Todd S. Emrick, Jayant Kumar, Ramaswamy Nagarajan Feb 2012

Halogen-Free Ultra-High Flame Retardant Polymers Through Enzyme Catalysis, Sethumadhavan Ravichandran, Subhalakshmi Nagarajan, Bon Choel Ku, Bryan Coughlin, Todd S. Emrick, Jayant Kumar, Ramaswamy Nagarajan

Todd S. Emrick

Over the past few years, the use of certain types of halogenated flame retardant additives such as decabromodiphenylether has come under intense scrutiny due to their toxicity, environmental persistence and bio-accumulation. There is an immediate need for the development of non-toxic alternative flame retardant materials and fire resistant polymers with comparable or better efficacies, obtained using benign synthetic approaches. Enzymatic polymerization is being used increasingly as an environmentally friendly alternative method for the synthesis of functional materials including polymers and additives. Here, we report a biocatalytic synthesis of a new class of thermally stable, ultra-fire resistant polyphenols based on deoxybenzoins ...


Multicompartment And Multigeometry Nanoparticle Assembly, Darrin J. Pochan, Jiahua Zhu, Ke Zhang, Karen L. Wooley, Caroline Miesch, Todd S. Emrick Jan 2011

Multicompartment And Multigeometry Nanoparticle Assembly, Darrin J. Pochan, Jiahua Zhu, Ke Zhang, Karen L. Wooley, Caroline Miesch, Todd S. Emrick

Todd S. Emrick

The directed or dynamic assembly of molecular components in solution is a simple and effective strategy to confine materials in desired geometries and length scales. We use a kinetic control strategy with block copolymer blending to construct complex nanoparticles through the demixing of unlike block copolymers within the same nanoscale particle. Successful nanoparticle construction relies on kinetic trapping of unlike block copolymers into the same nanoparticle with solution processing. Not only can we make nanoparticles with multiple internal compartments of a desired size, but we can also make nanoparticles of hybrid geometries (e.g. a blend of cylindrical and spherical ...


Pegylated Polymers For Medicine: From Conjugation To Self-Assembled Systems, Maisie J. Joralemon, Samantha Mcrae, Todd S. Emrick Jan 2011

Pegylated Polymers For Medicine: From Conjugation To Self-Assembled Systems, Maisie J. Joralemon, Samantha Mcrae, Todd S. Emrick

Todd S. Emrick

Synthetic polymers have transformed society in many areas of science and technology, including recent breakthroughs in medicine. Synthetic polymers now offer unique and versatile platforms for drug delivery, as they can be “bio-tailored” for applications as implants, medical devices, and injectable polymer-drug conjugates. However, while several currently used therapeutic proteins and small molecule drugs have benefited from synthetic polymers, the full potential of polymer-based drug delivery platforms has not yet been realized. This review examines both general advantages and specific cases of synthetic polymers in drug delivery, focusing on PEGylation in the context of polymer architecture, self-assembly, and conjugation techniques ...


Connecting Quantum Dots And Bionanoparticles In Hybrid Nanoscale Ultra-Thin Films, Ravisubhash Tangirala, Yunxia Hu, Maisie Joralemon, Qingling Zhang, Jinbo He, Thomas P. Russell, Todd S. Emrick Jan 2009

Connecting Quantum Dots And Bionanoparticles In Hybrid Nanoscale Ultra-Thin Films, Ravisubhash Tangirala, Yunxia Hu, Maisie Joralemon, Qingling Zhang, Jinbo He, Thomas P. Russell, Todd S. Emrick

Todd S. Emrick

Ligand-functionalized CdSe quantum dots and nanorods, and horse spleen ferritin bionanoparticles, were co-assembled at an oil-water interface, then used in polymerization at the interface, effectively cross-linking the assembled mixtures of nanoparticles into robust structures. Both ring-opening metathesis polymerization (ROMP), and imine formation, proved suitable for preparation of the desired ultra-thin films in the form of capsules and sheets. The nanoparticle-based films prepared by ROMP exhibit chemical stability, while those prepared by aldehyde-amine coupling could be disrupted by addition of acid. Characterization of these hybrid nanoparticle-based materials, using transmission electron microscopy (TEM) and fluorescence confocal microscopy, confirmed the presence of both ...


Polyester-Graft-Phosphorylcholine Prepared By Ring-Opening Polymerization And Click Chemistry, Beth M. Cooper, Delphine Chan-Seng, Debasis Samanta, Xiongfei Zhang, Sangram Parelkar, Todd S. Emrick Dec 2008

Polyester-Graft-Phosphorylcholine Prepared By Ring-Opening Polymerization And Click Chemistry, Beth M. Cooper, Delphine Chan-Seng, Debasis Samanta, Xiongfei Zhang, Sangram Parelkar, Todd S. Emrick

Todd S. Emrick

Phosphorylcholine (PC)-substitution on aliphatic polyesters is accomplished by click chemistry with PC-substituted azides.


Pegylated Silicon Nanoparticles: Synthesis And Characterization, P. K. Sudeep, Zachariah Page, Todd S. Emrick Oct 2008

Pegylated Silicon Nanoparticles: Synthesis And Characterization, P. K. Sudeep, Zachariah Page, Todd S. Emrick

Todd S. Emrick

Silicon nanoparticles were prepared and functionalized with alkene-terminated poly(ethylene oxide) to impart amphiphilic solution properties to the particles.


Self-Assembly Of Nanoparticles At Interfaces, Alexander Böker, Jinbo He, Thomas P. Russell, Todd S. Emrick Sep 2007

Self-Assembly Of Nanoparticles At Interfaces, Alexander Böker, Jinbo He, Thomas P. Russell, Todd S. Emrick

Todd S. Emrick

Developments in the assembly of nanoparticles at liquid–liquid interfaces are reviewed where the assemblies can be controlled by tuning the size of the nanoparticles and the chemical characteristics of the ligands. Both synthetic and biological nanoparticles are discussed. By controlling the type of ligands, uniform and Janus-type nanoparticles can be produced where, at liquid–liquid interfaces, subsequent reactions of the ligands can be used to generate crosslinked sheets of nanoparticles at the interface that have applications including novel encapsulants, filtration devices with well-defined porosities, and controlled release materials. By controlling the size and volume fraction of the nanoparticles and ...


Quantum Dots Coordinated With Conjugated Organic Ligands: New Nanomaterials With Novel Photophysics, Nathan L. Hammer, Todd S. Emrick, Michael D. Barnes Jun 2007

Quantum Dots Coordinated With Conjugated Organic Ligands: New Nanomaterials With Novel Photophysics, Nathan L. Hammer, Todd S. Emrick, Michael D. Barnes

Todd S. Emrick

CdSe quantum dots functionalized with oligo-(phenylene vinylene) (OPV) ligands (CdSe-OPV nanostructures) represent a new class of composite nanomaterials with significantly modified photophysics relative to bulk blends or isolated components. Singlemolecule spectroscopy on these species have revealed novel photophysics such as enhanced energy transfer, spectral stability, and strongly modified excited state lifetimes and blinking statistics. Here, we review the role of ligands in quantum dot applications and summarize some of our recent efforts probing energy and charge transfer in hybrid CdSe-OPV composite nanostructures


Study And Characterization Of Tobacco Mosaic Virus Head-To-Tail Assembly Assisted By Aniline Polymerization, Zhongwei Niu, Michael Bruckman, Venkata S. Kotakadi, Jinbo He, Todd S. Emrick, Thomas P. Russell, Lin Yang, Qian Wang Jun 2006

Study And Characterization Of Tobacco Mosaic Virus Head-To-Tail Assembly Assisted By Aniline Polymerization, Zhongwei Niu, Michael Bruckman, Venkata S. Kotakadi, Jinbo He, Todd S. Emrick, Thomas P. Russell, Lin Yang, Qian Wang

Todd S. Emrick

One-dimensional composite nanofibres with narrow dispersity, high aspect ratio and high processibility have been fabricated by head-to-tail self-assembly of rod-like tobacco mosaic virus assisted by aniline polymerization, which can promote many potential applications including electronics, optics, sensing and biomedical engineering.


Stabilization Of Α-Chymotrypsin At Air–Water Interface Through Surface Binding To Gold Nanoparticle Scaffolds, Brian J. Jordan, Rui Hong, Basar Gider, Jason Hill, Todd S. Emrick, Vincent M. Rotello May 2006

Stabilization Of Α-Chymotrypsin At Air–Water Interface Through Surface Binding To Gold Nanoparticle Scaffolds, Brian J. Jordan, Rui Hong, Basar Gider, Jason Hill, Todd S. Emrick, Vincent M. Rotello

Todd S. Emrick

Gold nanoparticles stabilize chymotrypsin (ChT) against denaturation at the air–water interface through catenation and preferential localization of the nanoparticles at the air–water interface with concomitant decrease in interfacial energy.


In Situ Observation Of Place Exchange Reactions Of Gold Nanoparticles. Correlation Of Monolayer Structure And Stability, Rui Hong, Joseph M. Fernández, Hiroshi Nakade, Rochelle Arvizo, Todd S. Emrick, Vincent M. Rotello May 2006

In Situ Observation Of Place Exchange Reactions Of Gold Nanoparticles. Correlation Of Monolayer Structure And Stability, Rui Hong, Joseph M. Fernández, Hiroshi Nakade, Rochelle Arvizo, Todd S. Emrick, Vincent M. Rotello

Todd S. Emrick

Place exchange reactions were studied using dye displacement: subtle changes in ligand structure greatly affected both the rate of displacement and the stability of the monolayer.


Mixed Monolayer Coverage On Gold Nanoparticles For Interfacial Stabilization Of Immiscible Fluids, Elizabeth Glogowski, Jinbo He, Thomas P. Russell, Todd S. Emrick Jul 2005

Mixed Monolayer Coverage On Gold Nanoparticles For Interfacial Stabilization Of Immiscible Fluids, Elizabeth Glogowski, Jinbo He, Thomas P. Russell, Todd S. Emrick

Todd S. Emrick

Gold nanoparticles covered with a mixed monolayer of n-dodecanethiol and 11-mercapto-1-undecanol were prepared and found to mediate the oil–water interface, providing access to stable water droplets in oil.


The Use Of 4-Substituted Pyridines To Afford Amphiphilic, Pegylated Cadmium Selenide Nanoparticles, Habib Skaff, Todd S. Emrick Nov 2002

The Use Of 4-Substituted Pyridines To Afford Amphiphilic, Pegylated Cadmium Selenide Nanoparticles, Habib Skaff, Todd S. Emrick

Todd S. Emrick

Amphiphilic cadmium selenide (CdSe) nanoparticles were prepared by surface functionalization with novel ligands 1 and 2, composed of pyridine moieties substituted in the 4-position with polyethylene glycol (PEG) chains.


Hyperbranched Porphyrins—A Rapid Synthetic Approach To Multiporphyrin Macromolecules, Stefan Hecht, Todd S. Emrick, Jean M. J. Fréchet Feb 2000

Hyperbranched Porphyrins—A Rapid Synthetic Approach To Multiporphyrin Macromolecules, Stefan Hecht, Todd S. Emrick, Jean M. J. Fréchet

Todd S. Emrick

A new class of porphyrin containing hyperbranched polymers has been prepared via proton-transfer polymerisation utilising an A2 + B3 approach, thus providing an accelerated entry into the construction of branched multiporphyrin architectures.