Agnieszka Tomala

Cracow University of Technology | PK · Faculty of Materials Science and Physics

Background: Poly(glycerol sebacate) is a polymeric material with potential biomedical application in the field of tissue engineering. In order to act as a biodegradable scaffold, its incubation study is vital to simulate its behavior. Objectives: This study explores the degradation of porous poly(glycerol sebacate)/hydroxyapatite scaffolds subje...

Hard bone disease is a clinical problem affecting more than 20 million people annually worldwide, with significant health, social, and economic consequences. For successful integration of any implant, the key aspects are bone regeneration, osseointegration at the bone–implant interface, and the mitigation of inflammation. The purpose of this resear...

In an increasingly aging society, there is a growing demand for the development of technology related to tissue regeneration. It involves the development of the appropriate biomaterials whose properties will allow the desired biological response to be obtained. Bioactivity is strongly affected by the proper selection of active ingredients. The aim...

Bioactive calcium phosphate ceramics (CaPs) are one of the building components of the inorganic part of bones. Synthetic CaPs are frequently used as materials for filling bone defects in the form of pastes or composites; however, their porous structure allows modification with active substances and, thus, subsequent use as a drug carrier for the co...

Hydroxyapatite (HAp) constitutes a significant inorganic compound which due to its osteoinductivity, osteoconductivity as well as the ability to promote bone growth and regeneration is widely applied in development of biomaterials designed for bone tissue engineering. In this work, various synthesis methodologies of HAp based on the wet precipitati...

The biomaterial coatings for bone tissue regeneration described in this study promote bioactivity. The ceramic-polymer composite coatings deposited on polylactide (PLA) plates contain polymers, namely polyvinylpyrrolidone (PVP)/polyethylene glycol (PEG), while the ceramic phase is hydroxyapatite (HA). Additionally, collagen (COL) and glutathione (G...

Nowadays, a great attention is directed into development of innovative multifunctional composites which may support bone tissue regeneration. This may be achieved by combining collagen and hydroxyapatite showing bioactivity, osteoconductivity and osteoinductivity with such biocompatible polymers as polyvinylpyrrolidone (PVP) and poly(vinyl alcohol)...

Polymer and hydroxyapatite (HAP) composites have growing interest in bone regeneration. Commonly used for these applications is polyvinylpyrrolidone (PVP), which represents excellent biological inertness, is biocompatible, and do not adversely interact with HAP. For this reason, in our studies, we have focused on 3-igreedient biocomposites based on...

Regenerative medicine is becoming a rapidly evolving technique in today’s biomedical progress scenario. Scientists around the world suggest the use of naturally synthesized biomaterials to repair and heal damaged cells. Hydroxyapatite (HAp) has the potential to replace drugs in biomedical engineering and regenerative drugs. HAp is easily biodegrada...

This works investigates the in-situ formation of MoS2 and WS2 tribofilms by the synergy between transition metal oxide nanoparticles and conventional sulphur-containing anti-wear and extreme pressure additives. The formation of these low friction tribofilms can be obtained under reciprocating sliding contact and under extreme pressure conditions, a...

The issues associated with sealing operation are of vital significance due to their function in mechanics. The most universal, simple, and cheap solution of seals are O-rings. They are most commonly used for all seals. The article evaluates the operation characteristics of an O-ring seals under operation with oils containing MoS2 nanoparticles. The...

Carbon nanodots (CDs) are extensively explored due to their little toxicity, excellent water solubility, and biocompatibility. Particularly, fluorescent CDs have received ever-increasing attention. Nevertheless, up to now, only a few findings have been dedicated to measuring the tribological properties of doped CDs, especially Ga doped CDs (Ga@CDs...

One of the most important drawbacks limiting the application of MoS 2 nanotubes (NTs) as an oil additive is their temperature sensitivity. Recent studies showed that MoS 2 NTs can be substituted by MoO 3 NTs in conjunction with S-containing lubricants by exploiting a novel approach of in-situ tribochemical sulphurization. The objective of this work...

The paper presents the first use of nanolubricants containing MoS2 nanotubes for form tapping of zinc-coated steel. MoS2 nanotubes are known for their superb low frictional, anti-wear and extreme pressure properties and have shown a promising performance as nanolubricant additive in many machining and forming applications. However their interfacial...

MoS2 nanotubes are known to enhance the tribological properties of lubricants thanks to support friction-reducing and anti-wear properties. However, in fully-formulated lubricants particularly for steel elements, other properties such as oxidation and corrosion protection are also necessary to provide a comprehensive lubricating performance and pro...

MoS2 nanotubes (NTs) are novel lubricant additives reducing friction and wear of mechanical components made of steel. Nowadays, non-ferrous surfaces are becoming more widely used, mainly as multifunctional coatings working in configuration with a steel pair. As a consequence, the purpose of this work is to reveal the interaction mechanism of nanopa...

MoS2 nanoparticles are typically obtained by high temperature sulfurization of organic and inorganic precursors in S rich atmosphere and have excellent friction reduction properties. We present a novel approach for making the sulfurization unnecessary of MoO3 nanotubes during the synthesis process for friction and wear reduction applications while...

The use of transition metal dichalcogenides nanoparticles is an emerging concept in lubrication for enhancing the tribological properties of lubricants. However, in fully-formulated products other properties are essential for providing a comprehensive protection against degradation. Therefore, the coexistence of nanoparticles with conventional addi...

Nanoparticles based on transition metal dichalcogenides (TMD) are considered to hold great promise as boundary lubricating additive/material for improving friction and wear of engineering functional surfaces. However, TMD nanoparticles cannot provide a comprehensive surface protection against oxidation, corrosion or sludge control. Therefore, the c...

The layered structure of transition metal dichalcogenides makes them promising materials for self-lubricating films. Transition metal dichalcogenide films can be considered as substitute for carbon-based self-lubricating films in several varieties of environmental conditions. The tribological properties of these films at high load have been studied...

Tribological research concerning sliding contacts at temperatures of 500–1000 °C has received limited attention. Industrial systems operating under high temperatures can be readily found in sheet metal forming processes. The control of friction during the tool–workpiece interaction and minimisation of tool wear are both crucial in maintaining the p...

The use of different process media such as cutting fluids, coolants, honing oil and washing media in typical machining operations exceeds 5,000 m3 per year. These media support critical functions such as lubrication, corrosion protection, cleaning and cooling, and have an enormous effect on the manufacturing performance. The tribological properties...

Tribological research concerning sliding contacts operating at elevated temperatures has received very limited attention so far, despite its importance for reliable, safe and efficient operation of many tribological systems. Typical examples can be found in aerospace, power generation and metal working industry. Considerable differences induced by...

The physical and chemical composition of surfaces determine various important properties of solids such as corrosion rates, adhesive properties, frictional properties, catalytic activity, wettability, contact potential and - finally and most importantly - failure mechanisms. Very thin, weak layers (of man-made and biological origin) on much harder...

A tools lifetime absolutely depends on the material properties and lubrication. By a lubricant absence, the direct contact between the materials might cause an increase of friction and wear, which might lead to a tool's failure. That is why wear prediction and control are important requirements in industry.The wear prediction experiments in this st...

Functional additives, particularly extreme-pressure and antiwear additives, in formulated oil will compete to adsorb and form a protective layer in tribological contacts. The thickness of the layer is determined by the equilibrium between the formation and removal processes. In this article, the interactions between additives and base oil molecules...

The objective of the present work is to evaluate the influence of carbon content on nanotribological response of reactively sputtered W-S-C thin film. Towards that purpose, W-S-C film containing varying amount of carbon was deposited on tool steel substrate using reactive sputtering. The nanohardness and lateral force microscopy of these films are...

The mechanical and frictional properties of hydrogen- and oxygen-terminated nanocrystalline diamond films (NCD) grown by hot-filament chemical vapor deposition (HFCVD) have been investigated in the present work. The structure and morphology of the NCD films have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) a...

Additives in lubrication technology perform by physically or chemically adsorbed films on tribological surfaces. In water lubricated tribosystems when the environment is very corrosive the additives effect is especially important. Typically applied corrosion inhibitors neutralize pH of contaminants in the fluid. Ethanolamines and ethylamines are kn...

Transition metal dichalcogenides with a layered structure are well known for their self-lubricating properties, particularly in a vacuum or dry atmosphere. The macrotribological properties of these films have been studied extensively. However, the tribological behaviour of these films in the nanonewton load range has hardly been reported. Study of...

Fully formulated water lubricating fluids have been thoroughly described in literature. However, the influence of individual additives on tribological properties of these compositions is still not fully clear.In this paper we present frictional, anti-wear and anti-corrosion properties for separate solutions of anti-corrosion, anti-foaming and anti-...

Functional additives, particularly extreme pressure and antiwear additives, in formulated oil will compete to adsorb and function in tribological contacts. A low-polarity commercial base oil, poly-α-olefin (PAO), blended with zinc dialkyl dithiophosphates (ZDDP) has been studied. The tribological performance was evaluated using a ball-on-disk test...

Transition metal dichalcogenides have a layered structure and are therefore promising self-lubricating films. They can be considered as potential substitutes for carbon based films in various environmental conditions. In this work, acomparative atomic force microscopy study of co-sputtered Mo-Se-C and W-S-C films is performed to evaluate their nano...

Ball on disc tribometer and atomic force microscopy (AFM) were used to analyse the effect of base oil polarity on the friction behaviour of steel–steel contacts lubricated with base oil + zinc dialkyldithiophosphate (ZDDP) solutions. Understanding the lubrication properties of the first chemisorbed layer of additives on work pieces yields important...

The aim of present study was to find out the influence of oxygen and nitrogen containing ethanolamine oligomers on the tribological behavior. X-ray photo electron spectroscopy (XPS) was used to obtain insight into the molecular mechanisms leading to the macroscopic lubricity. Monomolecular lubricant films were deposited onto ultrathin copper films...

Ethanolamines are used in tribology as anti-corrosion additives and as cutting fluids in metal working. Goal of the present study was an experimentally based theory of the lubricating properties of ethanolamines from the nano- via the micro- to the macroscopic scale. The different ethanolamine oligomers (monoethanolamine, diethanolamine and trietha...

Fully formulated metalworking fluids have been thoroughly described in literature, but the influence of individual additives on tribological performance of such compositions is still not fully clear. In this study we want to establish the mechanism of how different additives affect tribological properties of the system, and to select the best compo...

The morphologies of chemical vapour deposited (CVD) diamond films can be changed over a wide range by controlling the process parameters of the deposition. The surface morphologies of the film in turn, govern the micro- and nanomechanical properties of the film. In view of these, diamond films having three different types of morphologies namely coa...

Thermoluminescent properties of intrinsic CVD diamond samples synthesized with oxygen added in the gas phase during crystal growth were investigated. Sensitivity and linearity were evaluated over the 0.2–45 Gy dose range, using Cs-137 and Co-60 γ-ray sources. Extremely high sensitivity was observed at doses exceeding 1 Gy, and poor reproducibility,...