Mykhaylyk, Oleksandr O. - University of Sheffield

个人简介

Dr. Sasha Mykhaylyk obtained his MSc in Physics (optics and spectroscopy) from Taras Shevchenko Kiev State University in 1991 (Diploma with distinction was awarded on graduation). After obtaining a PhD in solid state physics and crystallography from the Institute for Problems of Materials Science (the Ukrainian Academy of Sciences) in 1996, he became a Research Scientist at the same institute where he was later promoted to a Senior Scientist. After holding Royal Society/NATO Fellowship at the University of Cambridge in 2000-2001 he joined the University of Leeds in 2002 as a Research Associate. He moved to the University of Sheffield in 2004 where he was promoted to a Research Fellow in 2011.

研究领域

Scattering methods Much of my research focuses on the structural analysis of soft matter materials and in particular polymers. We live in a Golden age of Materials Science and Biology, based on a solid underpinning from Chemistry and Physics. One of the keys to this success is recent progress in structural characterization techniques where scattering methods, giving access to structural organization of matter from atomic scales to microns, occupy a dominating role. Experimental data obtained by scattering methods (SAXS, WAXS, XRD, SANS and SLS) provide structural information associated with Fourier space. My research investigates how this information can be transformed into real space, convenient for our understanding. This involves structural modelling, Monte-Carlo simulations and Fourier transformation techniques. An advantage of scattering methods is that they can be used for kinetic studies of materials in-situ in different environments. Therefore, an other aspect of my work is design of dedicated experimental set-ups for studying materials under external impact such as shear flow or extensional flow, temperature or pH changes. I have a continuous interest in fat crystallization, colloids and nanoparticles structure, in particular core-shell systems (examples of my research are nanodiamonds to carbon onions transition, a phase separation of polyurethane confined by a nanosized spherical shell). My current research is on thermo-responsive block-copolymer micelles and vesicles. Mechano-optical rheologyResearch Oleksandr Mykhaylyk Rheology is widely recognized as a basic method in processing of polymers, food and cosmetics. In addition, visualization can be used as an effective tool for studying phenomena taking place in fluids. Since soft matter materials subjected to flow often demonstrate a related anisotropy in their refractive index and stress, this causes birefringence visualizing the flow. I have recently developed a new combinatorial technique, shear-induced polarized light imaging (SIPLI), for rheo-optical measurements of polymeric liquids. The SIPLI technique has already been successfully used for studying shear-induced nucleation and crystallization of polyolefins (see the figure), fibrillation in natural silks and flow alignment of block-copolymer self-assembled structures. My present research focuses on further development of SIPLI for in-situ studies of shear-induced phenomena such as stress, orientation and structural transitions taking place in gels, polymers, copolymers, liquid crystals and colloids. Polymer crystallization Microstructure of solidified polymers depends on thermo-mechanical process history. In general, processed thermoplastics are composed of two structural morphologies: spherulitic (isotropic) and shish-kebab (anisotropic). Ratio of these morphologies in the end-product controls its mechanical properties and material performance. While spherulitic structure is reasonably understood there is still no a reliable theory for structural formation of shear-induced shish-kebabs. My work is on physical understanding of how the formation of shear-induced morphologies is related to polymer polydispersity, thermodynamics and flow conditions. Based on our research we have proposed a four-stage model for shish-kebab formation including stretching of molecules, nucleation, aggregation and fibrillation.

近期论文

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Mable CJ, Thompson KL, Derry MJ, Mykhaylyk OO, Binks BP & Armes SP (2016) ABC Triblock Copolymer Worms: Synthesis, Characterization, and Evaluation as Pickering Emulsifiers for Millimeter-Sized Droplets. Macromolecules, 49(20), 7897-7907. View this article in WRRO Yang P, Mykhaylyk OO, Jones ER & Armes SP (2016) RAFT Dispersion Alternating Copolymerization of Styrene with N-Phenylmaleimide: Morphology Control and Application as an Aqueous Foam Stabilizer. Macromolecules, 49(18), 6731-6742. View this article in WRRO Akpinar B, Fielding LA, Cunningham VJ, Ning Y, Mykhaylyk OO, Fowler PW & Armes SP (2016) Determining the Effective Density and Stabilizer Layer Thickness of Sterically Stabilized Nanoparticles. Macromolecules. View this article in WRRO Derry MJ, Fielding LA, Warren NJ, Mable CJ, Smith AJ, Mykhaylyk OO & Armes SP (2016) In situ small-angle X-ray scattering studies of sterically-stabilized diblock copolymer nanoparticles formed during polymerization-induced self-assembly in non-polar media. Chemical Science, 7, 5078-5090. View this article in WRRO Mykhaylyk OO, Warren NJ, Parnell AJ, Pfeifer G & Laeuger J (2016) Applications of shear-induced polarized light imaging (SIPLI) technique for mechano-optical rheology of polymers and soft matter materials. Journal of Polymer Science Part B: Polymer Physics, 54(21), 2151-2170. View this article in WRRO Draper ER, Mykhaylyk OO & Adams DJ (2016) Aligning self-assembled gelators by drying under shear. Chem. Commun., 52(42), 6934-6937. View this article in WRRO Jones ER, Mykhaylyk OO, Semsarilar M, Boerakker M, Wyman P & Armes SP (2016) How Do Spherical Diblock Copolymer Nanoparticles Grow during RAFT Alcoholic Dispersion Polymerization?. Macromolecules, 49(1), 172-181. View this article in WRRO Mable CJ, Gibson RR, Prevost S, McKenzie BE, Mykhaylyk OO & Armes SP (2015) Loading of Silica Nanoparticles in Block Copolymer Vesicles during Polymerization-Induced Self-Assembly: Encapsulation Efficiency and Thermally Triggered Release. Journal of the American Chemical Society, 137(51), 16098-16108. View this article in WRRO