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Dr in¿. Mariusz Wo¼niak
Personal Data

Position:
Phone:
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Assistant Professor
(+48) 22 116 32 77
mariusz.wozniak@ifpan.edu.pl 		Mariusz Wo¼niak
Research Interests
  • Optical characterization of nanoparticles and aggregs of nanoparticles
  • Electromagnetic models and light scattering techniques
  • Complex particles description and modeling
Projects
Aggregates

Recent publications
  1. J. Archer, M. Kolwas, G. Derkachov, M. Wo¼niak, D. Jakubczyk, K. Kolwas, Optical diagnostics of surfaces of single evaporating liquid microdroplet of solutions and suspensions, Proc. SPIE 9884, Nanophotonics VI, 988427 (April 19, 2016); DOI:10.1117/12.2225786 
  2. M. Wo¼niak, G. Derkachov, K. Kolwas, J. Archer, T. T. Wojciechowski, D. Jakubczyk and M. Kolwas, Formation of Highly Ordered Spherical Aggregates from Drying Microdroplets of Colloidal Suspension, Langmuir, (2015), DOI: 10.1021/acs.langmuir.5b01621,
  3. G. Derkachov, D. Jakubczyk, M. Wo¼niak, J. Archer, M. Kolwas, High-Precision Temperature Determination of Evaporating Light-Absorbing and Non-Light-Absorbing Droplets, J. Chem. Chem. B, 118, 12566−12574, (2014).
  4. R. Ho³yst, M. Litniewski, D. Jakubczyk, M. Zientara, M. Wo¼niak, Nanoscale transport of energy and mass flux during evaporation of liquid droplets into inert gas: computer simulations and experiments, Soft Matter, 9, 7766 (2013).
Ph.D. Thesis
Wozniak M., Characterization of nanoparticle aggregates with light scattering techniques, Ph.D. thesis (in English); Marseille (France): Aix-Marseille University, 2012, WozniakM_PhD_2012.pdf.

This Ph.D. work provides and evaluates various solutions to characterize, with electromagnetic (optical) methods nanoparticles and aggregates of nanoparticles found in suspensions, aerosols and dusty plasmas...

Particles modelling
  • DLA/DLCA fractal-like aggregates
The fully adjustable (tunable) DLA-type code was developed. It allows to generate aggregates with precisely defined morphological parameters, strict self-similarity and scale-invariant properties [1].
DLCA code is under construction...
  • Buckyball-like aggregates
To model very dense and highly opaque aggregates observed in aerosols we developed a "Buckyball-like" model [2].

Fractal-like aggregate
Numerically generated fractal-like aggregate

  1. Wo¼niak M., Onofri F., Barbosa S., Yon J., Mroczka J., Comparison of methods to derive morphological parameters of multi-fractal samples of particle aggregates from TEM images, Journal of Aerosol Science, vol. 47, pp. 12-26, 2012.
  2. Onofri F. R.A., Barbosa S., Toure O., Wo¼niak M., Grisolia C., Sizing buckyballs-like aggregates of colloidal nanoparticles by light extinction spectroscopy, Journal of Quantitative Spectroscopy and Radiative Transfer, 2012, DOI 10.1016/j.jqsrt.2012.08.018
Light Extinction Spectroscopy (LES)

LES technique measures beam transmission of particles illuminated by a polychromatic beam [1]. The beam transmission depends on particles size distribution, concentration and intrinsic properties.
This leads to an ill-posed problem which requires to inverse a Fredholm integral equation of the first kind. It was solved with the least-square algorithm with a non-negative constraint.
The experimental validation for nano silica beads, tungsten aggregates [2] and dusty plasma [1,3] proves potential of the LES technique.
SEM image
SEM image of buckyball-like aggregates of nano silica beads

  1. Onofri F., Wo¼niak M., Barbosa S., On the optical characterization of nanoparticle and their aggregates in plasma systems, Contributions to Plasma Physics, vol. 51, pp. 1-9, 2011.
  2. Onofri F. R.A., Barbosa S., Toure O., Wo¼niak M., Grisolia C., Sizing buckyballs-like aggregates of colloidal nanoparticles by light extinction spectroscopy, Journal of Quantitative Spectroscopy and Radiative Transfer, 2012, DOI 10.1016/j.jqsrt.2012.08.018.
  3. Onofri F., Barbosa S., Wo¼niak M., Mroczka J., Vrel D., Grisolia C., In-situ characterization of dust mobilized by laser cleaning methods and loss of vacuum accident, Fusion Science and Technology, vol. 61 (1), pp. 39-45, 2012.
TEM analysis of fractal-like aggregates

As a reference for scattering techniques [1] methods for the TEM-based analyses were developed [2].
A newly developed Modified Box-Counting Method (MBC) was found to provide less noisy estimation for the evolution of the fractal dimension with the size of aggregates than widely used multi-scale analysis. With the MBC method the mean fractal dimension of the experimental soot sample is lower (1.66±0.02) than the one derived with the classical multi-scale analysis (1.88±0.02).
TEM image
TEM images of soot (left) and dusty
plasma (right) aggregates

  1. Mroczka J., Wo¼niak M., Onofri F.R.A., Algorithms and methods for the analysis of the optical structure factor of fractal aggregates, Metrology and Measurement Systems, vol. 19 (3), pp. 459-470, 2012.
  2. Wo¼niak M., Onofri F., Barbosa S., Yon J., Mroczka J., Comparison of methods to derive morphological parameters of multi-fractal samples of particle aggregates from TEM images, Journal of Aerosol Science, vol. 47, pp. 12-26, 2012.

International cooperation

IUSTI UMR CNRS n°7343, Aix-Marseille University, Marseille, France,
Fabrice Onofri, Ph.D. D.Sc, Director of Research at CNRS, personal website.


  
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