A5073388486- Force Microscopy Techniques and Applications
- Polymer Surface Interaction Studies
- Advanced Materials and Mechanics
- Adhesion, Friction, and Surface Interactions
- Polysaccharides Composition and Applications
- Advanced Polymer Synthesis and Characterization
- Semiconductor Lasers and Optical Devices
- Mechanical and Optical Resonators
- Polymer crystallization and properties
- Cellular Mechanics and Interactions
- Advanced Optical Network Technologies
- Hydrogels: synthesis, properties, applications
Duke University
2023-2024
The mechanical properties of covalent polymer networks often arise from the permanent end-linking or cross-linking strands, and molecular linkers that break more easily would likely produce materials require less energy to tear. We report cyclobutane-based mechanophore cross-linkers through force-triggered cycloreversion lead are up nine times as tough conventional analogs. response is attributed a combination long, strong primary strands cross-linker scission forces approximately fivefold...
The advent of covalent adaptable networks (CANs) through the incorporation dynamic bonds has led to unprecedented properties macromolecular systems, which can be engineered at molecular level. Among various types stimuli that used trigger chemical changes within polymer networks, light stands out for its remote and spatiotemporal control under ambient conditions. However, most examples photoactive CANs need transparent they exhibit slow response, side reactions, limited penetration. In this...
Slide-ring gels are polymer networks with cross-links that can slide along the chains. In contrast to conventional unentangled fixed chains, slide-ring strain-softening and distribute tension much more uniformly between their strands due so-called "pulley effect". The sliding of also reduces elastic modulus in comparison same number density strands. We develop a single-chain model account for redistribution monomers network primary chain. This takes into both pulley effect fluctuations per...
Both polymer size and chain elasticity depend on long-range bond correlations. These correlations are gradually cut off for higher externally applied force thus increasing stiffness. We develop a theory tension-dependent validate it with simulations. Our model explains the stiffness measured in single-molecule spectroscopy experiments compared scattering of unperturbed chains.
Extending polymer chains results in a positive chain tension, fch, primarily due to conformational restrictions. At the level of individual bonds, however, fb, is either negative or and depends on both tension bulk pressure. Typically, bond are assumed be directly related. In specific systems, this dependence may not intuitive, whereby fch increases while fb decreases; i.e., entire extended bonds compressed. Specifically, increasing grafting density brush extension along direction...