A5003102245- Membrane Separation Technologies
- Block Copolymer Self-Assembly
- Fuel Cells and Related Materials
- Membrane Separation and Gas Transport
- Polymer crystallization and properties
- Membrane-based Ion Separation Techniques
- Nanopore and Nanochannel Transport Studies
- Organometallic Complex Synthesis and Catalysis
- Zeolite Catalysis and Synthesis
- Rheology and Fluid Dynamics Studies
- Advanced Polymer Synthesis and Characterization
- Theoretical and Computational Physics
- Polymer Surface Interaction Studies
- Pickering emulsions and particle stabilization
- Advanced Sensor and Energy Harvesting Materials
- Advanced Mathematical Modeling in Engineering
- Polymer Nanocomposites and Properties
- Synthetic Organic Chemistry Methods
- Semiconductor Quantum Structures and Devices
- Advanced Drug Delivery Systems
- Material Dynamics and Properties
- Photonic and Optical Devices
- Dendrimers and Hyperbranched Polymers
- Process Optimization and Integration
- Nanoparticle-Based Drug Delivery
National Institute of Standards and Technology
2020-2023
Government of the United States of America
2023
National Institute of Standards
2020
Princeton University
2017-2019
University of Pennsylvania
2012-2014
nLIGHT (United States)
2003
Colloids with internally structured geometries have shown great promise in applications ranging from biosensors to optics drug delivery, where the internal particle structure is paramount performance. The growing demand for such nanomaterials necessitates development of a scalable processing platform their production. Flash nanoprecipitation (FNP), rapid and inherently colloid precipitation technology, used prepare colloids blends block copolymers homopolymers. As revealed by combination...
Methods for the preparation of narrow-distribution ROMP polycyclopentene are developed to suppress rate acyclic metathesis: reaction between active metal-carbene chain end and an olefin in medium. In particular, we investigate interchain metathesis, which generates linear polymers with "scrambled" lengths, demonstrate formation ring by intrachain backbiting quantify their content product. By controlling relative rates propagation versus these side reactions, prepare low dispersity...
Comtinuous-wave (cw) operation of organometallic vapor phase epitaxy-grown In0.4Ga0.6As0.995N0.005 quantum well (QW) lasers has been realized, at a room-temperature near-threshold emission wavelength 1.295 μm, with threshold-current density 220 A/cm2 for 2000 μm cavity-length (Lcav) devices. A threshold current only 615 was achieved cw temperature 100 °C, an 1.331 μm. maximum cw-output power 1.8 W obtained InGaAsN QW cavity lengths 1000 and heat-sink 20 °C.
Thin film composite membranes can selectively separate mono- and divalent ions from water via solution-diffusion of each species through a dense but ultrathin, highly cross-linked polymer "skin" layer; is transported across the membrane faster than associated salts. Changing selectivity layer typically requires adjusting monomer chemistries that make up layer, doing so also impacts host other properties. Here, we employ electrostatic layer-by-layer deposition inorganic nanoparticles to...
Malaria poses a major burden on human health and is becoming increasingly difficult to treat due the development of antimalarial drug resistance. The resistance issue further exacerbated by lack patient adherence multi-day dosing regimens. This situation motivates new treatments that are less susceptible We have applied Flash NanoPrecipitation (FNP), polymer-directed self-assembly process, form stable, water-dispersible nanoparticles (NPs) 50–400 nm in size containing OZ439, poorly orally...
We investigate the fundamental mechanism of spray-assisted layer-by-layer (LbL) assembly oppositely charged silica nanoparticles. Alteration major operating parameters such as suspension concentration, spray flow rate, and duration allows us to develop a kinetic model for LbL deposition. The spray-deposition is broken down into two sequential mass transport steps: bulk flux substrate surface followed by random motion nanoparticles through thin liquid film that adheres throughout procedure....
We present a series of polyamide membranes synthesized via molecular layer-by-layer (mLbL) deposition trimesoyl chloride (TMC) and 3,5-diaminobenzoic acid (BA). These exhibit superior NaCl rejection compared to previously reported TMC–BA prepared interfacial polymerization with the improved performance mLbL films attributable higher cross-link density facilitated by stepwise process in good solvents. compare from TMC m-phenylenediamine (MPD), conventional reverse osmosis membrane chemistry....
A new diblock copolymer chemistry, hydrogenated poly(n-hexyl norbornene)-block-poly(cyclohexyl norbornene), is demonstrated to undergo a lower critical ordering transition (LCOT) upon heating. Diblock copolymers exhibiting LCOT behavior are rare, and our knowledge, the system described in this work first all-hydrocarbon species do so. Furthermore, tendency toward demixing for polymer at high temperatures does not arise from large free volume mismatch between its components, mechanism most...
ABSTRACT The ever‐growing catalog of monomers being incorporated into block polymers affords exceptional control over phase behavior and nanoscale structure. segregation strength, χ N , is the fundamental link between molecular‐level detail thermodynamics. However, predicting mandates at least one experimental measurement for each pair blocks. This typically requires access to disordered state. We describe a method estimating from small‐angle X‐ray scattering measurements interfacial width...
We present a series of polyamide membranes synthesized via molecular layer-by-layer (mLbL) deposition using combination two acid chlorides, trimesoyl chloride (TMC) and isophthaloyl (IPC), one diamines, m-phenylenediamine (MPD) or 3,5-diaminobenzoic (BA). These monomer combinations permit comparison the conventional reverse osmosis chemistry, TMC combined with MPD, against variant higher concentration polar groups, BA, reduced cross-link density addition linear monomer, 50%/50% mixture by...
Abstract Cyclopentene (C) and norbornene (N) may both be enchained by ring‐opening metathesis polymerization (ROMP). N homopolymerizes to essential completion, but C has a significant equilibrium monomer concentration, [C] eq = 1.17 m at 30 ° C. While cannot homopolymerize below , it can still in copolymerizations with N. A terminal kinetic model, where one shows depropagation competitive propagation, well represents experimental data for the “living” ROMP copolymerization of Mo‐based...
The thermodynamic interaction strengths between linear polyethylene (PE) and members of a family hydrogenated polynorbornenes prepared by ring-opening metathesis polymerization can be tuned across wide range via the choice substituent appended to polynorbornene backbone at 5-position. Isopropyl certain n-alkyl groups yield that are highly miscible with PE, capable producing symmetric diblock copolymers homogeneous melts molecular weights in excess 100 kg/mol. In contrast, phenyl-substituted...
The low-strain mechanical properties of linear polyethylene (PE) can be substantially altered by the incorporation a short block polymer with high glass transition temperature (Tg) into majority-PE copolymer. In particular, yield stress and tensile modulus sharply increased addition relatively small fraction glassy block, especially when combined thermal history that promotes crystallinity crystal thickness PE block. For example, 15 wt % hydrogenated poly(norbornyl norbornene) (Tg = 115 °C)...
Using ambient-pressure XPS, we investigate the chemical interaction between water and polyamide membranes, to understand transport in desalination membranes.
Polyamide (PA) nanofilm membranes for solvent filtration are widely used in various industries. However, reliable models that can describe transport PA have yet to be developed owing measurement challenges associated with the highly irregular, ultrathin, and crosslinked structure which hampers accurate estimation of solvent-membrane affinity. In this study, we determined Hansen solubility parameters (HSPs) by quantifying swelling degrees a molecular layer-by-layer-assembled, model solvents...