International audienceThe European Polysaccharide Network of Excellence (EPNOE) is a research and education network connecting 16 academic and research institutions and a large number of companies with its focus on polysaccharide expertise development and polysaccharide-related research for innovation in business and industry. EPNOE has two main missions in the field of polysaccharide applications in materials, food, and pharmacy/medicine, which are to organise education in polysaccharide science and to perform basic and applied research for the development of new products derived from polysaccharides. In 2009, the EPNOE network prepared a research road map vision to 2020 focussed on polysaccharide use in material structuring, food and health, taking both research and education into consideration. The research road map was prepared from various social, political, industrial and scientific inputs coming from within and outside EPNOE: (1) results of four brain-storming sessions by EPNOE scientists and students, (2) individual contributions of EPNOE scientists and (3) individual contributions of scientists outside EPNOE through an internet review. The result is described in this article

The main objective of this study was to obtain chitosan functionalized viscose fabric with improved antibacterial properties and washing durability. In this regard carboxyl and aldehyde groups, as binding points for irreversible chitosan attachment into/onto viscose fabric, were introduced by two different pretreatments: 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO) oxidation and coating with TEMPO oxidized cellulose nanofibrils (TOCN). The Fourier transform infrared spectroscopy, elemental analysis, zeta potential measurements, scanning electron microscopy, breaking strength and antibacterial testing were used to evaluate the influence of these pretreatments on chitosan binding, but also on chemical, electrokinetic, morphological, mechanical and antibacterial properties of pretreated and chitosan functionalized viscose fabrics. Washing durability of chitosan functionalized viscose was monitored through changes in the chitosan content, electrokinetic and antibacterial properties after multiple washing. TOCN coating improves mechanical properties of fabric, while TEMPO oxidation deteriorates them. The results show that both pretreatments improve chitosan adsorption and thus antibacterial properties, which are highly durable to washing. After five washings, the chitosan functionalized pretreated viscose fabrics preserve their antibacterial activity against Staphylococcus aureus, while antibacterial activity against Escherichia coli was lost. TOCN coated and chitosan functionalized viscose fabric is a high value-added product with simultaneously improved antibacterial and mechanical properties, which may find application as medical textiles.

Oxygen plasma treatment was applied in order to improve the adsorption of chitosan onto viscose fabric. Modification of the surface and adsorption of chitosan was monitored by determination of XPS spectra, determination of contact angles from rates of water imbibition, and conductometric titration. The plasma treatment resulted in hydrophilization of the surfaces through oxidation. The hydrophilic surfaces were stable for at least 24 h. The treatment also yielded binding sites that resulted in over 20% increase of the amount of chitosan adsorbed over that adsorbed on nontreated fabric. Layers of chitosan adsorbed after plasma treatment were substantially more active as antimicrobial agents than those on nontreated surfaces.

Adsorption of chitosan nanoparticles with embedded iodine was implemented onto pristine and oxidized cellulose viscose fabrics in order to introduce antimicrobial and antioxidative functionalization. The adsorption capacity, charging behavior and electrokinetic response of differently functionalized viscose at different pH values were analyzed by determining their zeta potential. Desorption studies, besides zeta potential measurements, were supported by polyelectrolyte titration. Finally, the antimicrobial properties were evaluated by the standard ASTM E2149 method, whilst antioxidative properties were determined by 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation decolorization assay. It was found that the oxidation of viscose fabrics further modified by chitosan–iodine nanoparticles dispersion was a very promising functionalization process, providing good coating stability along with antimicrobial and antioxidant properties.

Different treatment processes such as alkaline washing, bleaching, and slack-mercer ization are used to improve the sorption characteristics of cellulose fibers. The differences between the sorption properties of cellulose fibers are measured with tensiometry, and their sorption velocities are measured with liquids of different polarities. From those measurements, contact angles are determined using the Washburn equation. The surface free energy of the cellulose fibers is determined from contact angle data obtained with the Owens-Wendt-Rabel-Kaeble approximation. Results show that among these treatments, slack-mercerization produces the lowest contact angle and the highest surface free fiber energy, and has therefore the largest influence on sorption ability. Viscose fibers (raw and treated) have the lowest contact angle and the highest surface free energy, and are the most hydrophilic compared to lyocell and modal fibers. This is explained by their crystalline structure and the accessibility of their surface groups to polar liquids.

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Different ways are presented of modifying cellulosic non-woven substrates, which can serve as potential wound dressings with satisfactory antimicrobial and hydrophilic properties. For safe attachment of silver particles without a measurable release from the used materials, a sol–gel derived process was used. Alkaline and oxygen plasma treatments were used to improve the hydrophilicity of the materials. Their efficiency was determined by measuring contact angles and water retention values. Scanning electron microscopy (SEM) was used for determination of sample morphology prior to and after treatment. The efficiency of silver attachment and activity was evaluated by in vitro release studies and antimicrobial tests. Atomic force microscopy (AFM) and SEM, combined with dynamic light scattering, were used for determination of silver particle size. Additionally, we evaluated the influence of treatment on technological parameters, important for application performance, i.e. mechanical properties and air permeability.