Dawid Stawski

Extreme biomimetic approach for developing novel chitin-GeO2 nanocomposites with photoluminescent properties

This work presents an extreme biomimetics route for the creation of nanostructured biocomposites utilizing a chitinous template of poriferan origin. The specific thermal stability of the nanostructured chitinous template allowed for the formation under hydrothermal conditions of a novel germanium oxide-chitin composite with a defined nanoscale structure. Using a variety of analytical techniques (FTIR, Raman, energy dispersive X-ray (EDX), near-edge X-ray absorption fine structure (NEXAFS), and photoluminescence (PL) spectroscopy, EDS-mapping, selected area for the electron diffraction pattern (SAEDP), and transmission electron microscopy (TEM)), we showed that this bioorganic scaffold induces the growth of GeO2 nanocrystals with a narrow (150–300 nm) size distribution and predominantly hexagonal phase, demonstrating the chitin template’s control over the crystal morphology. The formed GeO2–chitin composite showed several specific physical properties, such as a striking enhancement in photoluminescence exceeding values previously reported in GeO2-based biomaterials. These data demonstrate the potential of extreme biomimetics for developing new-generation nanostructured materials.

Solvothermal synthesis of hydrophobic chitin–polyhedral oligomeric silsesquioxane (POSS) nanocomposites

Chitinous scaffolds isolated from the skeleton of marine sponge Aplysina cauliformis were used as a template for the deposition of polyhedral oligomeric silsesquioxanes (POSS). These chitin-POSS based composites with hydrophobic properties were prepared for the first time using solvothermal synthesis (pH 3, temp 80 °C), and were thoroughly characterized. The resulting material was studied using scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and thermogravimetry. A mechanism for the chitin-POSS interaction after exposure to these solvothermal conditions is proposed and discussed.

Preparation of monolithic silica–chitin composite under extreme biomimetic conditions

Chitin is a widespread renewable biopolymer that is extensively distributed in the natural world. The high thermal stability of chitin provides an opportunity to develop novel inorganic-organic composites under hydrothermal synthesis conditions in vitro. For the first time, in this work we prepared monolithic silica-chitin composite under extreme biomimetic conditions (80°C and pH 1.5) using three dimensional chitinous matrices isolated from the marine sponge Aplysina cauliformis. The resulting material was studied using light and fluorescence microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy. A mechanism for the silica-chitin interaction after exposure to these hydrothermal conditions is proposed and discussed.

Antibacterial properties of polypropylene textiles modified by poly(2-(N,N-dimethyloamino ethyl) methacrylate)

Polypropylene nonwoven fabrics samples were modified using poly(2-(N,N-dimethyloamino ethyl) methacrylate) (PDAMA) and silver-containing layers. The structure of the material after modification was confirmed using scanning electron mocroscope, energy-dispersive X-ray spectroscopy, Fourier Transfer Infrared Spectroscopy (FTIR), and electro-kinetic measurements. It was found that samples with external PDAMA layers have excellent activity against Staphylococcus aureus under dynamic contact conditions. In contrast, samples finished with deposited silver showed little antimicrobial effect. Antibacterial tests conducted under static conditions showed no antibacterial activity irrespective of the deposited layers.

Deposition of poly(ethyleneimine)/poly(2-ethyl-2-oxazoline) based comb-branched polymers onto polypropylene nonwoven fabric using the layer-by-layer technique. selected properties of the modified materials

Well-defined comb polymers consisting of branched homo poly(ethyleneimine) (bPEI), or poly(ethyleneimine) with grafted poly(2-ethyl-2-oxazoline) (PEI-PEtOx), having varying degrees of polymerization (DPs) of the main chain and branches, have been successfully deposited onto a poly(propylene) nonwoven textile fabric (PP) using a layer-by-layer technique. The surface properties of the materials have been studied by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Changes in the net surface charge and the electrostatic behaviour have been studied by employing electrokinetic and electrostatic measurements. The deposition of the electrolytes increased the thermal stability of the nanomaterials and enabled the absorption of copper ions from solution.

N,N,N-trimethyl chitosan as an efficient antibacterial agent for polypropylene and polylactide nonwovens

Abstract The paper presents a method of depositing N,N,N-trimethyl chitosan (TMC) layers onto polypropylene and polylactide nonwovens. A two-step modification procedure is applied: first, grafting the nonwovens with acrylic acid and next layer-by-layer deposition. Turbidimetric measurements confirm the creation of polycomplexes between grafted poly(acrylic acid) and deposited TMC. The created material structure is evaluated using gravimetric analysis, reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy measurements and pH-metric titration. The modified material exhibits good antibacterial properties against Gram-positive bacteria Staphylococcus aureus.

Thermogravimetric Analysis of Sponge Chitins in Thermooxidative Conditions

Structural aminopolysaccharide chitin possesses diverse physicochemical properties which are important principal for use of this biopolymer in technology. Recently, special attention has been paid to the thermostability of chitin because of its potential application in hydrothermal synthesis with the aim to obtain novel nanostructured metal oxide-based composite materials. It was shown that chitin is still stable in the range of temperatures between 100 and 400 °C. Here, chitins from different origins have been studied with respect to investigate their thermostability using thermogravimetric analysis.

Producing a poly(N,N-dimethylaminoethyl methacrylate) nonwoven by using the blowing out method

A poly(N,N-dimethylaminoethyl methacrylate) nonwoven was produced by the blowing out technique. The basic structural and mechanical properties of the obtained material were measured and described. It was found that the formed nonwoven has a smooth and delicate structure with quite weak mechanical properties. Its antibacterial properties against Staphylococcus aureus and Escherichia coli bacteria were shown. Some medical applications were suggested.

PLA nonwovens modified with poly(dimethylaminoethyl methacrylate) as antimicrobial filter materials for workplaces

The objective of the present study was to assess the antimicrobial effectiveness of silver- and copper-modified polylactide (PLA)–poly(dimethylaminoethyl methacrylate) (PDMAEMA) nonwovens used as materials for the production of air purifying respirators. The antimicrobial activity of six types of PLA nonwovens, with different PDMAEMA, Ag, and Cu contents, were tested using the ATCC 100 method. Microorganisms were isolated from the air in 12 workplaces within composting plants, tanneries, and museums. Dominant bacterial and fungal species were identified using 16S RNA and ITS1/2 molecular analysis, respectively. Air samples collected from the composting plant and tannery were highly contaminated with bacteria, while those from museums with fungi (103–104 CFU/m3). We identified potentially pathogenic microorganisms from the following genera: Bacillus, Corynebacterium, Pseudomonas, Candida, Aspergillus, Penicillium, Scopulariopsis, and Paecilomyces. PLA nonwovens containing 5.1% poly(dimethylaminoethyl methacrylate) and 2.7% Ag or 3.8% Cu exhibited good antimicrobial properties (R > 99.9%) against the pathogenic strains found in the above workplaces. These nonwovens also have good inspiratory resistance parameters.