Samaniuk Research Group Home

The Samaniuk Lab studies the rheology of soft materials and interfaces, with an emphasis on linking rheology and morphology. We are highly interdisciplinary in our use of rheological tools and the application of rheology, and currently have ongoing projects studying 2D materials confined to fluid-fluid interfaces, investigating the interfacial rheology of cyclopentane hydrates, developing new active microrheological techniques, and investigating the rheology of conditioned soils for underground tunneling applications. Other areas in which we routinely make measurements are in the study of lignocellulosic biomass rheology, and high pressure and temperature rheology for oil and gas applications. We are primarily an experimental laboratory with a range of conventional bulk rheological tools, and we are equipped with custom interfacial rheological tools. One of our strengths is in the development of rheological tools, equipment, and methods, to study challenging materials such as those with large heterogeneities, high yield stresses, or those that require high temperatures and pressures.



Interfacial rheology of cyclopentane hydrates

Cyclopentane hydrates can be formed and studied at atmospheric pressure, and temperatures that are accessible in the lab. This makes these hydrates a good candidate to study fundamental aspects of hydrate formation and dissociation, and also to seek connections between interfacial properties and the rheological properties of bulk hydrate rheology.




Dynamics of 2D materials at fluid-fluid interfaces

Monolayer MoS2 at an air-water interfaceThe particles of 2D materials can be confined to a fluid-fluid interface where they can be assembled to form larger structures and subsequently deposited onto solid substrates. We have found that 2D particles have unique interactions when at a fluid-fluid interface that determine the structures formed, and that these interactions are not well understood. The image to the left is of monolayer molybdenum disulfide (MoS2) particles at an air-water interface that have self-assembled into a circular domain.


Active microrheology

Brownian Motion GIFMicrorheology is a technique where micron-size particles can be used to determine the rheology of the material in which they are immersed, or embedded. Passive microrheology relies on thermal energy to move the probe particles (shown in the GIF to the left), while active microrheology relies on external forces to move the probe. An example is the use of electromagnetic coils to drive the motion of magnetic particles. One set of our 1D tweezer apparatus is shown below.


Rapid underground tunneling

Underground tunneling requires the management of drilling fluids pumped at high flow rates in order to remove rock and soil at sufficient rates. Increasing tunneling speed is a goal of the tunneling community that requires understanding the relationship between pressure drop, drilling mud viscosity, and the viscosity of the soil slurry as it returns to the surface. We are currently searching for a postdoctoral researcher to lead the construction and implementation of a flow loop for testing these highly shear-thinning materials under a recently funded DARPA grant (see below for position details).


Asphaltenes at fluid-fluid interfaces

Asphaltenes_Fluorescence MicroscopyAsphaltenes are natural molecules in crude oil that stabilized oil-water emulsions. This is beneficial in some aspects of processing oil, but detrimental in others. The ability to alter the stability of asphaltene-stabilized emulsions is a great processing advantage, and we are equipped with the tools necessary to investigate the structure and rheology of asphaltene molecules confined to fluid-fluid interfaces. The image to the left was obtained on our inverted microscope using fluorescence microscopy to observe model asphaltene molecules at an air-water interface. These molecules form complex structures that give rise to unique interfacial rheological properties that have consequences for emulsion stability.


Rapid underground tunneling

We seek to hire a postdoctoral researcher on a project titled “Advancing Rapid Tactical Tunneling Operations (ARTTO)”, funded by the Department of Defense. The project aims to increase the speed of underground tunneling by a factor of ten beyond the state of the art, which requires the design of custom shear-thinning drilling fluids, the construction of a flow loop to study soil-slurry rheology, and the investigation of the effects of fluid hydraulic pressure on soil stability.

The postdoc will build a flow loop to study the rheological properties of soil slurries that will be encountered during drilling, prepare custom shear-thinning drilling fluids, and study the influence of pressure on tunnel and soil stability. Collaboration with the Civil and Environmental Engineering Department and the Petroleum Engineering Department at the Colorado School of Mines will be an integral part of the project. Partial supervision of the PhD student on the project is expected. The position is for 15 months and can begin as early as October 1.

Candidates should have a PhD in chemical, mechanical, or civil engineering, and the ideal candidate should have a strong background in experimental fluid dynamics.

Interested applicants can send a cover letter and CV directly to Dr. Samaniuk. Applications will be considered on a rolling basis.