2020-2023 Efficient fabrication of single-particle-thick micropaths, their characterization and applicability.

Funder: Polish National Science Centre (OPUS17, 2019/33/B/ST5/00935), PLN 2 160 200

The objectives of this research project are: (i) to develop methods for efficient fabrication of single-particle-thick structures and their deposition on substrates in a form of micropaths, (ii) to understand the mechanical and electrical properties of the assembled chain-like structures, (iii) to investigate viability of the produced particle micropaths with respect to their usage in various applications, including in flexible electronics. The useful properties of the single-particle-resolution structures, such as high surface-to-volume ratio, long-range ordering, or periodicity at mesoscale, can be harnessed in a variety of devices, including optical, biosensing, photovoltaic, and electronic devices. There are several strategies and techniques for assembling particles in chain-like structures on substrates. Yet, each of the methods has one or (commonly) more of the following disadvantages: it is expensive, time-consuming, inefficient, unsuitable for formation of non-linear structures, unable to position the particle microstructures in a designed fashion, or suitable for formation of structures only in bulk liquids; requires access to advanced tools and laboratories; or enables assembly of particle structures with limited lengths. Thus, the assembly of single-particle-resolution micropaths with controlled length and well-behaved configuration in a simple and effective way is still a great challenge. This hugely hinders the possible applicability of such structures and development of new materials and devices. The proposed research is a response to this problem. An electric field–assisted route for side by side particle deposition on substrates is proposed here. The method overcomes all of the abovementioned limitations and enables high-throughput organization of particles on a variety of different substrates at low cost.

2020-2022 Electric-field-induced deformation and crumpling of non-spherical particle shells formed on droplets.

Funder: Polish National Science Centre (Preludium17, 2019/35/N/ST5/02821), PLN 120 720

Adding particles to a droplet surface may alter droplet behaviour and characteristics when subjected to compressive stress. Several research groups have studied the deformation, mechanics, relaxation, and rheological properties of particle-covered droplets and described their differences from the behaviour of particle-free droplets under stress. The majority of these studies concern droplets with spherical shells or capsules. However, very little is known about the behaviour of droplets with shells made of arrested particles, that is, non-spherical droplets covered by densely packed particles, and the literature lacks studies on this subject. We aim to change this and contribute to filling the gap in this research area. The objective of this work is to understand and describe the behaviour of non-spherical Pickering droplets with particle shells subjected to compressive stress. We will use an electric field to induce electric stress on a Pickering droplet, which will enable the non-contact exertion of force on it and measurements of numerous mechanical and rheological properties of the droplet and its particle shell.

2016-2020 Mechanical properties, specific release and motility of patchy colloidosomes.

Funder: Polish National Science Centre (OPUS10, 2015/19/B/ST3/03055), PLN 1 162 000

Within the project, we studied patchy particle capsules initially made on a surface of liquid droplets. The investigation concerned the mechanical properties; specific direction and targeted release of encapsulated species; and the motility of such heterogeneous colloidal capsules (patchy colloidosomes). The main objectives of the project were: to further develop fabrication methods of patchy colloidosomes and hybrid patchy colloidal capsules on the bases of my recent pioneering work in this field; to understand the mechanism of complex deformation of patchy colloidal capsules; to develop routes for specific and targeted release of encapsulated species from patchy colloidosomes; and research on the guided-motion, self-propulsion and collective behaviour of patchy colloidosomes.

2017-2019 Electric field driven propulsion and collective dynamics of homogeneous and patchy capsules.

Funder: European Commission (H2020-MSCA-IF-2016), EUR 134 462

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.

2015-2017 Mechanical properties and instability of Pickering films and emulsions.

Funder: Polish National Science Centre (FUGA, 2015/16/S/ST3/00470), PLN 286 000

This is a research project in experimental soft matter physics focused on understanding the mechanics and rheology of monolayered colloidal capsules and instabilities of Pickering droplets probed by electrically induced stress. Within the project, we study colloidal capsules (composed of jammed particles) made on a surface of oil droplets. The investigation concerns the viscoelastic deformation, crumbling, rotation or tank-treading of a single capsule due to applied external E-fields. We also monitor changes of mechanical properties of droplets as the Pickering emulsion is being produced. This work is conducted in collaboration with group at NTNU, Trondheim.

2013-2015 A new approach to fabricating various colloidal shells and Pickering emulsions.

Funder: Foundation for Polish Science (HOMING PLUS, 2013-7/13), PLN 309 000

This project focuses on new methods of fabrication of Colloidosomes/Janus/Patchy/Arrested shells. We also produce an active colloidal armour, i.e. a pupil-like shell that contracts and expands in presence of E-fields. We study silicone oil droplets, containing different particles (including clay, PE. PS or conductive beads), that are submerged in immiscible organic oil, and we observe particle movement, oil circulation and drop deformation when an electric field is applied. Results show how electric field strength, electrohydrodynamics, dielectric and conductive properties determine the fluid flow, particle organization and drop deformation. Adsorption and assembly of colloidal particles at the surface of liquid droplets is the basis for particle-stabilized Pickering emulsions and colloidosome capsules.