Physics of Complex Fluids Group

The research goal of PCF is to understand and to control liquids and their interfaces from molecular to macroscopic scales. Our research connects fundamental phenomena in static and dynamic wetting, nanofluidics, microfluidic two-phase flow, functional surfaces, drop impact, and drop evaporation to practically relevant applications such as enhanced oil recovery, lab-on-a-chip systems, analytical chemistry (MALDI-MS), optofluidics, and inkjet printing.

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Experimental methods and tools: electrowetting, high resolution Atomic Force Microscopy and spectroscopy, (high speed) video microscopy, contact angle goniometry, particle tracking microrheology, macroscopic rheometry, (imaging) ellipsometry, quartz crystal microbalance, Langmuir trough and Langmuir-Blodgett deposition.

Latest news


MESA+ soft matter+ day

We are very proud to announce the 2nd Soft Matter+ day of the University of Twente! Coupled to the Soft Matter+ colloquium series, the Soft Matter+ Day aims to bring together and showcase the excellent Soft Matter work performed within the university of Twente and the MESA+ institute for nanotechnology. The day will be held on the 2nd of June 2016, will take place in The Gallery and will start around 10AM ... read more

Congratulations Dr. Liu

On Thursday, May 19th, Fei Liu successfully defended his PhD thesis entitled “A study of interaction forces at a solid-liquid interface using AFM”. In his work, Fei developed and validated various methods of atomic force spectroscopy in fluid environment to extract both conservative and dissipative forces in molecularly thin liquid films. In particular, he noticed demonstrated an unexpectedly strong increase of the viscous dissipation at the interface between aqueous electrolytes and highly charged mineral surfaces that demonstrate the limitations of standard electric double layer theory.
We are happy that Fei will stay for a few more months at PCF before leaving for a(nother) postdoc appointment in Norway. We wish Fei all the best for his future carrier. ... read more

祝賀 (congratulations) Dr. Wang!

On 20 april, Lei Wang successfully defended her PhD thesis, entitled: “Adsorption at solid-liquid interfaces, studied with surface sensitive techniques”.
Key elements in her work were the use of microfluidics, ellipsometry and QCM to detect the adsorption of small molecules. The challenges this brings with measuring small signals, were picked up by various opponents via critical questions as well as compliments. In the end all were satisfied, and Lei got her degree after 4 years at PCF. We wish her success in her future career! ... read more

Resolving clay mineral surfaces – from periodic atomic structure to surface defects. New publication in Nanoscale

Atomic scale details of surface structure play a crucial role for solid-liquid interfaces. While macroscopic characterization techniques provide averaged information about bulk and interfaces, high resolution real space imaging reveals unique insights into the role of defects that are believed to dominate many aspects of surface chemistry and physics. Here, we use high resolution dynamic Atomic Force Microscopy (AFM) to visualize and characterize in ambient water the morphology and atomic scale structure of a variety of nanoparticles of common clay minerals adsorbed to flat solid surfaces. Atomically resolved images of the (001) basal planes are obtained on all materials investigated, namely gibbsite, kaolinite, illite, and Na-montmorillonite of both natural and synthetic origin. Next to regions of perfect crystallinity, we routinely observe extended regions of various types of defects on the surfaces, including vacancies of one or few atoms, vacancy islands, atomic steps, apparently disordered regions, as well as strongly adsorbed seemingly organic and inorganic species. While their exact nature is frequently difficult to identify, our observations clearly highlight the ubiquity of such defects and their relevance for the overall physical and chemical properties of clay nanoparticle-water interfaces. ... read more