A5027743490- Force Microscopy Techniques and Applications
- Mechanical and Optical Resonators
- Cellular Mechanics and Interactions
- Hydrogels: synthesis, properties, applications
- biodegradable polymer synthesis and properties
- Metal-Organic Frameworks: Synthesis and Applications
- Lipid Membrane Structure and Behavior
- Adhesion, Friction, and Surface Interactions
- Advanced Fluorescence Microscopy Techniques
- Advanced Polymer Synthesis and Characterization
- Phosphorus and nutrient management
- Polymer Nanocomposites and Properties
- Carbon Nanotubes in Composites
- Machine Learning in Materials Science
- Advanced Electron Microscopy Techniques and Applications
- Synthetic Organic Chemistry Methods
- Christian Theology and Mission
- X-ray Diffraction in Crystallography
- Molecular Junctions and Nanostructures
- Organic Electronics and Photovoltaics
- Adsorption and biosorption for pollutant removal
- Polymer Surface Interaction Studies
- Religion, Society, and Development
- Conducting polymers and applications
- Advanced Sensor and Energy Harvesting Materials
Duke University
2018-2025
Durham Technical Community College
2018-2019
Hope College
2015-2018
Longer and stronger; stiff but not brittle Hydrogels are highly water-swollen, cross-linked polymers. Although they can be deformed, tend to weak, methods strengthen or toughen them reduce stretchability. Two papers now report strategies create tough deformable hydrogels (see the Perspective by Bosnjak Silberstein). Wang et al . introduced a toughening mechanism storing releasable extra chain length in part of double-network hydrogel. A high applied force triggered opening cycling strands...
Multi-mechanophore polymers provide advantages in characterization and function relative to chain-centered, single mechanophore polymers.
Symmetry forbidden reactions are notoriously difficult to study experimentally, for the simple reason that their competing symmetry allowed pathways typically dominate. Covalent polymer mechanochemistry offers an opportunity broaden access reactions, through judicious placement of handles on mechanophore reactants. Here, single molecule force spectroscopy and computation used evaluate substituent effects disrotatory ring opening reaction cyclobutene butadiene. Theory experiment reveal...
The fracture of rubbery polymer networks involves a series molecular events, beginning with conformational changes along the backbone and culminating chain scission reaction. Here, we report covalent gels in which macroscopic "reaction" is controlled by mechanophores embedded within mechanically active network strands. We synthesized poly(ethylene glycol) (PEG) through end-linking azide-terminated tetra-arm PEG (Mn = 5 kDa) bis-alkyne linkers. Networks were formed under identical conditions,...
Woodward and Hoffman once jested that a very powerful Maxwell demon could seize molecule of cyclobutene at its methylene groups tear it open in disrotatory fashion to obtain butadiene (Woodward, R. B.; Hoffmann, The Conservation Orbital Symmetry. Angew. Chem., Int. Ed. 1969, 8, 781–853). Nearly 40 years later, was discovered, the field covalent polymer mechanochemistry born. In decade since our befriended, many fundamental investigations have been undertaken build up understanding...
Mechanochemical reactions that lead to an increase in polymer contour length have the potential serve as covalent synthetic mimics of mechanical unfolding noncovalent "stored length" domains structural proteins. Here we report force-dependent kinetics stored release a family domain polymers based on cis-1,2-substituted cyclobutane mechanophores. The is determined by size (n) fused ring [n.2.0] bicyclic architecture, and it can be made sufficiently large (>3 nm per event) individual...
We report the mechanochemical activity of copolymers formed through radical addition polymerization cyclobutene carboxylates that are fused to larger rings. The ring repeats act as stored-length mechanophores along polymer backbone, and so these polymers a rare example high mechanophore content by polymerization. monomers amenable controlled techniques, specifically reversible addition-fragmentation chain transfer (RAFT) copolymerization with butyl acrylate, which enables comparative studies...
Metal-organic frameworks (MOFs) are extremely porous, crystalline materials with high surface area for potential use in gas storage, sequestration, and separations. Toward incorporation into structures these applications, this study compares three variations of surface-bound free-standing HKUST-1 MOF structures: surface-anchored (surMOF) thin film, drop-cast bulk powder. Herein, effects ammonia interaction framework activation, which is removal guest molecules via heat, investigated. Impact...
Stretching or striking a hydrogel results in its acidification by up to 2 pH units. The mechanically robust offers promise as synthetic platform for adaptive aqueous systems.
<p>The utility and lifetime of materials made from polymer networks, including hydrogels, depend on their capacity to stretch resist tearing. In gels elastomers, those mechanical properties are often limited by the covalent chemical structure strands between cross-links, which is typically fixed during material synthesis. Here, we report networks in constituent lengthen through force-coupled reactions that triggered as reach nominal breaking point. Reactive strand extensions up 40%...
A new compound with the core luminescent dye unit diketopyrrolopyrrole (DPP), namely 3,6-dithiophen-2-yl-2,5-dihydropyrrole[3,4-c]pyrrole-1,4-dione (DTDPP), attached to 3,4-ethylenedioxythiophene (EDOT) was synthesized. From this monomer, polymer films were prepared on glassy carbon and indium tin oxide surfaces using cyclic voltammetry. The characterized voltammetry, chronocoulometry, atomic force microscopy. electropolymerization of monomer exhibits reversible electrochemistry that...
Correction for ‘Empowering mechanochemistry with multi-mechanophore polymer architectures’ by Brandon H. Bowser <italic>et al.</italic>, <italic>Polym. Chem.</italic>, 2018, <bold>9</bold>, 3583–3593.
<div><p>Here, we report covalent polymer gels in which the macroscopic fracture “reaction” is controlled by mechanophores embedded within mechanically active network strands. We synthesized poly(ethylene glycol) (PEG) through end-linking of azide-terminated tetra-arm PEG (M<sub>n </sub>= 5 kDa) with bis-alkyne linkers. Networks were formed under identical conditions, except that was varied to include either a <i>cis</i>-diaryl (<b>1</b>) or...
The utility and lifetime of materials made from polymer networks, including hydrogels, depend on their capacity to stretch resist tearing. In gels elastomers, those mechanical properties are often limited by the covalent chemical structure strands between cross-links, which is typically fixed during material synthesis. Here, we report networks in constituent lengthen through force-coupled reactions that triggered as reach nominal breaking point. Reactive strand extensions up 40% lead...
Here, we report covalent polymer gels in which the macroscopic fracture “reaction” is controlled by mechanophores embedded within mechanically active network strands. We synthesized poly(ethylene glycol) (PEG) through end-linking of azide-terminated tetra-arm PEG (M n = 5 kDa) with bis-alkyne linkers. Networks were formed under identical conditions, except that was varied to include either a cis -diaryl ( 1 ) or -dialkyl 2 linked cyclobutane mechanophore acts as mechanochemical “weak link”...