Softmatter.pl

Members

Zbigniew Rozynek

Zbigniew Rozynek

(group leader, from 2013)

I am a physicist specializing in the physics of emulsions and field-driven particle assembly. Although my research is fundamental in nature, many of our discoveries have applications or extensions outside the sub-field of soft matter physics that I study. I worked at Harvard University, USA, as a Fulbright scholar and returned to Poland in Oct 2019, where I continue my research at AMU, Poznan. I earned my Ph.D. degree in 2011 from the NTNU, Norway. In May 2015, I co-founded a technological company that two years later made its debut on the Warsaw Stock Exchange. Now, I am a scientific leader at CADENAS - another technological startup I co-founded. I have the skills and abilities to build trust among his team members by fostering an appreciative and open-minded culture. I am self-motivated and believe that science benefits society.


Khobaib Khobaib

Khobaib Khobaib

(Phd candidate, 2016-present)

The objective of my work is to understand and describe the behaviour of Pickering droplets with particle shells subjected to compressive stress. We use an electric field to induce electric stress on a Pickering droplet, which enables the non-contact exertion of force on it and measurements of numerous mechanical and rheological properties of the droplet and its particle shell. I also study the electric field-directed assembly and organization of particles at drop surfaces. In this regard, we study the effect of various parameters, including electric field strength, particle size, coverage, and electrical conductivity on the final arrangement of particles.


Former Members

Tomasz Kubiak

Tomasz Kubiak

(post-doc, 2018-2019)

I worked on developing a route for stimulating the release of the encapsulated liquid from microcapsules using low-intensity ultrasound. We showed that acoustic waves with the intensity of a few W/cm2 were capable of localized puncturing of the particle capsules The mechanism responsible for this phenomenon was related to the stretching ofthe inner liquid content, which exerted mechanical stress on the capsule's shell. The method allows smooth liberation of the liquid in one direction that enables accurate targeting. Such nonviolent and directional release is crucial, for example, for applications where the directional release of an active substance is preferable.


Alexander Mikkelsen

Alexander Mikkelsen

(post-doc, 2017-2019)

"Electric field driven propulsion and collective dynamics of homogeneous and patchy colloidal capsules", H2020-MSCA-Individual Fellowships-2016. Particle capsules, and especially patchy particle capsules are challenging to fabricate. To realize the potential applications of these capsules, it is also important to consistently produce capsules with tailored physical and mechanical properties. One of the objectives of this action was to combine microfluidic devices and electric fields for high-throughput fabrication of patchy capsules. Realizing this objective was also necessary to study the collective dynamics of multiple propelling capsules which was the last objective of this research project.


Dawid Surdeko

Dawid Surdeko

(MSc student, 2019)

Particle designed assembly inside drops or at their surfaces holds promise for a variety of practical applications, in particular for generation of new structures, such as patchy particles or capsules. In my work I used ultrasonic and electric fields to manipulate particles of different kinds in either silicone oil or water drops formed in castor oil. We primarily used three physical phenomena, namely acoustic radiation force, electrohydrodynamic flows and electrorheological effects to either arrange particles into chain- or ribbon-like structures, and to form columnar phases of packed particle discs. We studied various aspects of our approaches for particle assembly, including material type and particle concentration.


Joanna Banaszak

Joanna Banaszak

(MSc student, 2018)

"Fabrication of particle capsules and their manipulation in electric and acoustic fields". The experimental part of my thesis involved fabrication of polystyrene, polyethylene and polystyrene-polyethylene capsules from Pickering emulsion. These capsules were then tested for ultrasound-triggered release. We used ultrasonic waves with a frequency of 1 MHz and an acoustic power in range from 0 to 2.5 W/cm2. The obtained experimental results indicated that ultrasound - triggered release could be controllable and in specific directions


Peter Kesa

Peter Kesa

(post-doc, 2018)

The objective of my experimental work was to develop methods for efficient fabrication of patchy colloidosomes and hybrid patchy colloidal capsules, and understand the mechanism of complex deformation of patchy colloidal capsules, e.g., crumpling, elastic deformation, viscoelastic relaxation, shell unjamming, shell tearing, etc. Microfluidic chips that I used in my work were designed and produced by our collaborators from the Microfluidics and Complex Fluids Research Group of prof. Piotr Garstecki in Warsaw.


Marta Obrempalska

Marta Obrempalska

(MSc student, 2017)

"Formation of Pickering emulsions monitored by ultrasounds and optical micoscopy". The goal of this research was to form Pickering emulsions using electric field-induced coalescence of droplets. Firstly, the optical microscopy was used to study the dynamics of formation of Pickering emulsions, and also to optimized the route for formation of the stable emulsion. Then the Pickering emulsion fabrication process was monitored simultaneously by ultrasounds and optical microscopy. The ultrasounds were used to complement the optical microscopy observations. From the measurements of the changes of the relative attenuation coefficient and velocity of the sound propagating through the emulsion it was possible to perform simple quantitative analysis of the dynamics of the Pickering emulsion formation.


Magdalena Sobolewska

Magdalena Sobolewska

(intern, 2017)

I investigated electro-rotation of particle-covered droplets suspended in castor oil. It turned out, that such droplets behaved differently than particle-free droplets. Classically, the Quincke rotation of solid particles is described to be the particle size-independent. Here, we observed strong dependency of capsule size on the rotation frequency. Because the particle-covered droplets can be considered as a two phase system, i.e., bulk liquid has different properties than a particle shell, the critical strength of electric field needed for Quincke rotation and deformation of such Pickering droplet were also different than that of a pure droplet.


Jaroslaw Wojciechowski

Jaroslaw Wojciechowski

(MSc student, 2016)

"The influence of chemical modification of polystyrene micro- particles on their electric-field-induced organization". I researched on formation of 1D and 2D structures composed of polystyrene microparticles located both inside and on a surface of an oil droplet. By changing the dielectric properties of polystyrene microparticles, it was possible to tune the magnitude of electric forces acting on the particles, and as a result the particles could organize themselves into different structures. Experimental part of my work was done in the Microfluidics and Complex Fluids Research Group of prof. Piotr Garstecki.


Kamil Kacprzak

Kamil Kacprzak

(MSc student, 2015)

"New methods for fabricating Janus shells". Fabrication of patchy particle capsules has long been theorized by scientists able to design different models, but the actual production of them remains a challenge. Until now, only two approaches for fabrication of patchy colloidal shells were demonstrated. Unfortunately, those methods are not suitable for mass production of patchy colloidal capsules. In my work, I intended to design a microfluidic chip in which large quantities of different patchy colloidal shells would produced in controlled fashion. I demonstrated that by using microfluidics it was possible to form Janus particle shells. The remaining challenge is to control the concentration of particles that occupy the surface of a droplet.


Marzena Prus

Marzena Prus

(MSc student, 2015)

"New methods for fabricating Janus shells". Fabrication of patchy particle capsules has long been theorized by scientists able to design different models, but the actual production of them remains a challenge. Until now, only two approaches for fabrication of patchy colloidal shells were demonstrated. Unfortunately, those methods are not suitable for mass production of patchy colloidal capsules. In my work, I intended to design a microfluidic chip in which large quantities of different patchy colloidal shells would produced in controlled fashion. I demonstrated that by using microfluidics it was possible to form Janus particle shells. The remaining challenge is to control the concentration of particles that occupy the surface of a droplet.


Anna Kalicka

Anna Kalicka

(MSc student, 2014)

"Formation of patchy colloidal capsules and their pharmaceutical applications". My experimental work was on developing methods for formation of homogeneous and heterogeneous particle capsules. The capsules that I was designing were composed of micrometre size polymeric particles. Oil-in-oil droplets were used for fabrication of the capsules. The particles were firstly brought to the surface of a droplet and then, using an electric field, assembled into designed patterns to eventually form a colloidal shell. Subsequently the shell was sintered to form an elastic and permeable colloidal capsule. Such particle capsules were studied as carriers for drug molecules - as candidates for making smart drug delivery systems.