Supramolecular Solvent-Free Nanofluids
Event details
| Date | 25.06.2015 |
| Hour | 11:00 |
| Speaker |
Prof. John Texter of Easter MIchigan University Bio: Professor Texter has over 35 years’ experience in the fields of coating, polymers, colloids, emulsions, and advanced materials. He has over 200 publications including over 44 issued US Patents. He has been Editor-in-Chief of the Journal of Dispersion Science and Technology, Associate Editor of Nanoparticle Resesarch, and has worked for Strider Research Corporation and for Eastman Kodak Company in various areas of dispersion and emulsion technology. He consults in diverse areas related to dispersion and coating formulation and stability. He is an experienced lecturer, organizer, and technical project manager. |
| Location | |
| Category | Conferences - Seminars |
We show that auto-condensation of organoalkoxysilanes, followed by suitable anion exchange, produces solvent-free nanoparticle nanofluids we call organosiloxane supramolecular liquids. We find that classical liquid properties are exhibited with some distinct differences. We observe heat capacity anomalies manifested as lambda transitions in excess heat capacity centered around a glass transition (Tg) and around a freezing transition. The Tg-proximal lambda transition is the first experimental realization of an enthalpic phase transition overlying a glass transition. The existence of such a connection or coincidence has undergone decades of theoretical conjecture.
The second anomaly spanning the melting/freezing range is the first reported excess enthalpy ever reported for an experimental particulate fluid undergoing a phase transition. The integral enthalpy from these lambda transitions is quantitatively accounted for by the loss of specific surface area of the particles, and the associated surface free energy, upon freezing and upon cooling beneath the glass transition temperature. This system also is the first experimental particle system reported that exhibits multiphase coexistence that otherwise is frustrated from crystallizing due to polydispersity.
This new material and cousins to be similarly derived promise to become useful in developing soft-sphere potentials in the thermodynamics of polymeric liquids. Similarly composed nanofluids obtained by condensation on nanosilica core templates and surface decorated with both ionic liquid organic salt groups and with various reactive groups are exotic cross-linking agents that define new types of resins. Such agents can be used to counter embrittlement provided by nanofillers while increasing toughness. We show that such materials can be used to produce thin films including UV protective clearcoats and an interesting new family of adhesives.
The second anomaly spanning the melting/freezing range is the first reported excess enthalpy ever reported for an experimental particulate fluid undergoing a phase transition. The integral enthalpy from these lambda transitions is quantitatively accounted for by the loss of specific surface area of the particles, and the associated surface free energy, upon freezing and upon cooling beneath the glass transition temperature. This system also is the first experimental particle system reported that exhibits multiphase coexistence that otherwise is frustrated from crystallizing due to polydispersity.
This new material and cousins to be similarly derived promise to become useful in developing soft-sphere potentials in the thermodynamics of polymeric liquids. Similarly composed nanofluids obtained by condensation on nanosilica core templates and surface decorated with both ionic liquid organic salt groups and with various reactive groups are exotic cross-linking agents that define new types of resins. Such agents can be used to counter embrittlement provided by nanofillers while increasing toughness. We show that such materials can be used to produce thin films including UV protective clearcoats and an interesting new family of adhesives.
Practical information
- General public
- Free
Organizer
- SUNMIL (Prof. Stellacci)
Contact
- Quy Ong <[email protected]>