Seminarium: Advanced AFM methods to probe nanoscale surface properties

24 maj. 2018, 10:00 - 11:00
Luleå, E231, LTU
Publicerad: 23 maj 2018

Titel på seminariet: Advanced AFM methods to probe nanoscale surface properties
Talare: Dr. Illia Dobryden, Division of Surface and Corrosion Science, KTH

Sammanfattning

Nanoscale surface properties such as mechanical, wear, electrical are of paramount importance in many frontline investigations. In detail, nanomechanical surface mapping, friction and wear test of polymer coatings, nanocomposites and hydrogels can provide new insights into development and design of such materials to improve their performance. It can further be combined with probing local surface potential, in the case of conductive filler particles and conductive coatings, to provide a deeper understanding for corrosion protection. One of the best routes to probe such nanoscale properties is Atomic Force Microscopy (AFM) utilizing its various operational modes. However, in the case of soft materials, such as hydrogels, standard AFM methods can have limitations which arise from the use of contact mechanics models and the quasistatic force balance assumption. Thus, it is not possible to obtain good rheological characterization of a hydrogel and provide an accurate measure of surface and bulk viscous response. A good solution to overcome these limitations is multifrequency dynamic AFM, where the measured interaction force is a combination of both the elastic and viscous surface response. Here, Intermodulation AFM, which is a dynamic narrow band method and was quite recently introduced, has also been employed.

During the presentation the following investigated systems will be discussed:

  • Poly(ethyl methacrylate) (PEMA) and poly(isobutyl methacrylate) (PiBMA) with silica filler nanoparticles and polydimethylsiloxane (PDMS) with silica nanoparticles composites: with particular focus on probing interphase phenomena
  • A waterborne acrylic-melamine anti-corrosion coating: wear and stick-slip friction study
  • A contact lens hydrogel: ImAFM study utilizing a recently introduced interaction model
  • Polymer adsorption on nanocrystalline cellulose (CNC) via nanomechanical measurements
  • Examples of scanning Kelvin probe force microscopy measurements with ImEFM

Om talaren:

Illia Dobryden was awarded his PhD degree in Physics in June 2014 at Luleå University of Technology at division of Material Sciences, Experimental Physics subject, defending a thesis entitled: “Scanning probe microscopy studies of interaction forces between particles: emphasis on magnetite, bentonite and silica”. He continued as a research engineer in LTU till November 2015 at Division of Material Sciences, Experimental Physics with a main focus on Atomic Force Microscopy (AFM) measurements and AFM extendings. From 2015 he is currently working as a postdoctoral researcher at the Royal Institute of Technology (KTH) at Surface and Corrosion Science Department and Department of Applied Physics. His main research focus is on developing and applying new methods in AFM. On-going research projects are based on colloidal probe force and friction measurements, nanomechanical characterization of hydrogels, coatings and nanocomposites under controlled humidity. Characterization of particle-polymer interactions.

Also, development and application of new Intermodulation AFM technique and bridging different research fields employing this new method.