Physics of Complex Fluids Group

The PCF group performs experimental research focusing on the properties of liquids on scales ranging from a few nanometers to many micrometers. Our activities fall into the categories: i) nanofluidics, ii) (electro)wetting & microfluidics, iii) soft matter mechanics. We are mainly interested in fundamental physical mechanisms that may ultimately also break grounds for new technological applications in the future.

The PCF group is part of the MESA+ institute for Nanotechnology at the University of Twente.

Latest news

d_omkar

Congratulations, Omkar, on your doctor title!

On Friday, January 16th, Omkar Deshmukh successfully defended his PhD thesis entitled “Soft Microgel Particles at Fluid Interfaces”. The work covers many aspects of the behavior of temperature sensitive PNIPAM microgel particles upon adsorption to air-water and oil-water interfaces. It highlights the prominent role of elastic deformations of these very open and soft gel networks that stretch by more than 100%, as Omkar revealed amongst other things by careful surface pressure measurement. The defense was attended live by Omkar’s larger family back in India and by his wife and son directly in Twente. We wish Omkar and his family all the best for the future. ... read more

Nature Physics publication on wettability-independent bouncing

Nature Physics publication. Congratulations!!! Jolet de Ruiter’s work on “Wettability-independent bouncing on flat surfaces mediated by thin air films” was published on November 10 in Nature Physics. In this work, she demonstrates that drops of liquids with arbitrary surface tension can bounce on arbitrary surfaces, even completely wetting ones. Provided that the impact speed is not too high, a thin air layer that cannot get squeezed out fast enough during the impact process provides an air cushion, on which the drop can bounce. For water drops up to 15 bounces were observed on clean glass surfaces. The complete manuscript can be found here. ... read more

Renewed 5-year contract with BP

BP and the PCF group signed a new contract to continue their successful collaboration on fundamental aspects of enhanced oil recovery for another 5 years. The work will continue to focus on the physical and chemical processes underlying the success of low salinity water flooding. In this new program our earlier experiments using Atomic Force Microscopy and macroscopic characterization tools will by vibrational (Raman) spectroscopy to allow for identification of chemical species at the lateral resolution of optical spectroscopy. ... read more

Liquid_lenses

Paper: Tunable aspherical lenses (Scientific Report)

We demonstrate that liquid-liquid interface can be electrostatically modulated into a tunable and ideal aspherical lens by applying electric field to a drop entrapped in an aperture, controlled hydrostatically. This is achieved by manipulating the meniscus shape by simultaneously altering the electrostatic force and laplace pressure (backpressure). Electrostatic pressure alters the curvature of initial spherical drop, consequently changing marginal and paraxial focal lengths and thus reducing the longitudinal spherical aberration (LSA). Such adaptive lenses are not only tunable in focal length and LSA, but in the process, LSA is suppressed, yielding perfect lens and consequently achieving enhanced optical performance. We confirm our findings by optically imaging a square grid. ... read more