WEB Reversibly tuneable viscosity of anthracene-functionalized silicone oilWednesday (01.01.2020) 00:30 - 00:45 Part of:
In technical tribological systems, lubricants have to cover the complete parameter field of the application, e.g. temperature and pressure variations. As a consequence, the lubricant has not always the ideal properties for a specific operation point.
The reversible adaption of lubricant viscosities would allow for optimum design of tribological systems. Here, we demonstrate the variation of viscosity and friction of a modified silicone oil by ultraviolet radiation.
Polysiloxanes were functionalized with anthracene groups and exposed to light with wavelength of 365 nm and 254 nm, respectively, to program the molecular weight by anthracene dimer formation and cleavage.
The UV radiation initially increases the viscosity by a factor of up to 50 depending on the duration of exposure. As shown by rheometry, changing the wavelength of the irradiated light reversibly reduces and increases the viscosity. The impact on friction forces in a microtribological contact is shown.
The introduced system is a first step towards a programmable tribological system with tuneable tribological properties.