Professor Urszula NARKIEWICZ, Ph.D., D.Sc., Eng.
Szczecin, 2015-12-29
West Pomeranian University of Technology, Szczecin
Institute of Chemical and Environment Engineering
Pulaskiego 10
70-322 Szczecin
Review Report on PhD Thesis of Marcin Wysokowski, M.Sc., Eng.
entitled
“Development of Novel Inorganic-Organic Chitin-Based Materials Obtained Under
Extreme Biomimetic Conditions”
prepared base on invitation letter from the Dean of the Faculty of Chemical Technology of
Poznan University of Technology  Associate Professor Krzysztof Alejski, Ph.D., D.Sc., Eng.
(438/2013-2015, 20.10.2015)
Supervisor: Prof. Teofil Jesionowski, Ph.D., D.Sc., Eng.  Poznan University of
Technology (Poland)
Co-supervisor: Prof. dr. rer. nat. habil. Hermann Ehrlich  Technische Universitaet
Bergakademie Freiberg (Germany)
Choice of topic
Inorganic–organic hybrid materials are among the most interesting and promising types of
nanomaterials, and one of the most important challenges in nanotechnology is to obtain
nanomaterials with a hierarchical architecture, built from nano-bricks and designed based on
systems found in nature (biomimetics). In the course of millions of years of evolution, nature
has produced functional materials with unrivalled parameters that we would like to be able to
imitate – for example, to produce fibres with the strength of spider’s thread, construction
materials with the hardness of certain animal shells, and coatings as perfectly unwettable as
the lotus leaf.
It is generally considered that the processes taking place in nature occur in moderate
conditions (atmospheric pressure, ambient temperature, neutral pH), often in the presence of
biocatalysts, namely enzymes. Nonetheless, examples are known of processes taking place
in nature under extreme conditions, such as Arctic or hydrothermal. One example of a
material formed many centuries ago in extreme conditions is amber. However, the concept of
extreme biomimetics, as a technology for obtaining innovative bio-inspired materials in
1
extreme conditions, was introduced only recently (2010), and its originator, Professor
Hermann Ehrlich, is one of the two supervisors of Marcin Wysokowski’s work.
With regard to the facts outlined above, I am of the opinion that the topic of Marcin
Wysokowski’s doctoral thesis, titled “Development of New Inorganic–Organic Chitin-based
Materials Obtained in Conditions of Extreme Biomimetic Synthesis”, is highly innovative and
ideally aligned with the latest trends in contemporary materials science.
Aim and scope
The aim of the work was to obtain and analyse a new type of inorganic–organic hybrid
material based on chitin. The author decided to do this using a hydrothermal method,
producing hybrid nanomaterials using a chitin-based scaffolding obtained directly from the
skeletons of marine sponges and cuttlefish. Because the chitin matrices obtained are stable
up to 280 °C, they can be used in hydrothermal conditions to obtain hybrid nanomaterials in
combination with inorganic compounds. In this way the author produced the following
composites: chitin–SiO2, chitin–ZrO2, chitin–ZnO, chitin–Fe2O3 and chitin–GeO2.
The resulting materials were analysed using a whole spectrum of modern
experimental techniques, including X-ray diffraction, Fourier transform infrared spectroscopy,
high-resolution transmission and scanning electron microscopy, thermogravimetric analysis,
Raman spectroscopy, X-ray photoelectron spectroscopy, selected area electron diffraction,
and near-edge X-ray absorption fine structure (NEXAFS).
The work also included investigation of the electrochemical, photoluminescent and
antibacterial properties of individual products.
Presentation
The reviewed thesis of Marcin Wysokowski, M.Sc., Eng. consists of 172 pages, and refers to
364 cited works. It contains 47 figures and photographs, which are of very high quality. The
thesis is written in English, and it has been very diligently edited. At the end is a summary in
Polish, as well as summaries of individual chapters. This summary is editorially weaker than
other parts of the thesis – it contains misprints (such as “devpelopment”, “novelity”,
“allowd”) and examples of awkward language (e.g. [in Polish] “This property favours the use
of selected chitin skeletons as structural organic matrices for nucleation and growth in a wide
range of hydrothermal reactions.”) What does the author mean by “a wide range of
reactions”? Different compounds, different temperatures? Would it not have been simpler to
write “It is therefore possible to use chitin skeletons as organic matrices for the nucleation
and growth of many inorganic crystals in hydrothermal conditions”?
2
Could the author explain what he means by “The interdisciplinary nature of the work
consists in the application of a nonlinear approach to problems of biomimetics…”? The
work does not include any mathematical modelling (hence where does the nonlinear
approach come from?), and the interdisciplinary nature of the work results rather from
the combining of elements of knowledge from the fields of chemistry, physics, biology
and materials science.
Content
In the section containing an analysis of the literature, following a general introduction
familiarising the reader with the scope of the work, the author provides a review of the
literature covering problems of biomimetics, with particular emphasis on biomimetics in
extreme conditions. A subsequent subsection concerns literature relating to chitin as an
excellent structural matrix for producing the type of materials studied in the work. The final
subsection in this part concerns the literature on hydrothermal synthesis. The entire literature
review section is diligently compiled and may serve as a compendium of knowledge for
researchers wishing to undertake work in the field of extreme biomimetics.
In Chapter 3 the author presents his research goals. The main aim of the work is to
use chitin scaffoldings obtained from the skeletons of marine sponges and cuttlefish to
produce new inorganic–organic materials in hydrothermal conditions. This goal was achieved
using the materials and research methods described subsequently in Chapter 4.
The first stage in the synthesis of inorganic–organic materials was the preparation of
the matrix, namely the obtaining of chitin–silica biomaterials by way of hydrothermal
silicification of chitin matrices isolated from marine sponges. The process was carried out in
the presence of a mixture of ethanol, ammonia solution and a surfactant (TEOS). The chitin–
silica scaffoldings were subsequently used to obtain composites with the oxides of several
metals – zirconium, zinc, iron and germanium. All of these composites were obtained in
hydrothermal conditions, although each was obtained using a different reactor and under
different conditions – this does not present any difficulty, as they were not intended to be the
subject of comparison.
It was found that silica binds to the OH, C+O and NH groups of chitin via hydrogen
bonds.
In the chitin–ZrO2 composite, the nanoparticles of zirconium oxide are
approximately 100 nm in size, and the average size of the crystallites of monoclinic ZrO2
is 4–8 nm. In this case also it was found that zirconia interacts with silica via hydrogen
bonds. An attempt was made to use the resulting composite to remove heavy metals
from water, and promising results were obtained: 1 g of composite is capable of
3
adsorbing 20 mg of cadmium (2.5 times more than in the case of pure chitin). It would
appear, however, that in view of the properties of zirconium oxide (luminescence,
chemical resistance, biocompatibility), the chitin–zirconia composite may well find many
other interesting applications, for instance in biomedicine. Similar potential applications
can be expected for the chitin–ZnO composite, which the author tested for its bactericidal
properties. It might be used, for example, in wound dressing materials to remove Grampositive bacteria.
The average size of hematite crystallites in the chitin–Fe2O3 composite was
estimated at approximately 57 nm. Hematite was found to interact with the –NH and C=O
groups of chitin. The author investigated the possibility of using these composites as fillers of
activated carbon in supercapacitors – the results obtained were positive, and even showed
an increase in capacitance over successive cycles.
Samples of the produced chitin–GeO2 composite were found to contain large
(150–300 nm) crystallites of germanium oxide, but also nanocrystallites measuring
around 10 nm. This composite exhibits interesting luminescent properties. Its intensity of
autofluorescence is stronger than that of pure chitin or of pure germanium oxide also
obtained in hydrothermal conditions. This is explained by an increase in defects, caused by
the incorporation of nanofibres of the biopolymer into the GeO2 crystalline framework. This
phenomenon may form a basis for successful applications in medicine, in sensors and in
optoelectronics.
Overall assessment
The doctoral thesis written by Marcin Wysokowski contains very interesting experimental
results, described in a logical and ordered manner. The candidate was required to master an
entirely new, challenging and interdisciplinary field of knowledge – extreme biomimetics –
and completed that task excellently.
The literature studies contained in the thesis are exceptionally diligent, and the
number of citations to published works is impressive.
The author has fully attained the goal of the work, using chitin matrices obtained from
the skeletons of marine organisms to produce new inorganic–organic materials in
hydrothermal conditions, these being the composites chitin–SiO2, chitin–ZrO2, chitin–ZnO,
chitin–Fe2O3 and chitin–GeO2.
Praise should be given not only to the precise analysis of the composites obtained,
but also to the proposals of potential applications for them, and the testing of these in
laboratory conditions.
4
In summary, since the reviewed doctoral thesis of Marcin Wysokowski, M.Sc., Eng. in
my opinion fulfils the requirements of the Act on academic and artistic degrees and titles,
I propose to the Council of the Chemical Technology Faculty of Poznan University of
Technology that it be admitted to the further stages of the doctoral process. This thesis is
ready to be defended orally, in front of respective committee.
Moreover, in view of the high quality of the thesis itself and the impressive list of
publications by Marcin Wysokowski (24, including 22 in Thomson Reuters JCR list (total
IF=67.9), as well as three patents and 24 conference papers), I would like to propose to the
Council of the Chemical Technology Faculty of Poznan University of Technology that a
distinction be awarded for this thesis.
5