Anticoagulant activity of cellulose nanocrystals from isora plant fibers assembled on cellulose and sio2 substrates via a layer-by-layer approach

In this study, we report the isolation of cellulose nanocrystals (CNCs) from Isora plant fibers by sulfuric acid hydrolysis and their assembly on hydrophilic cellulose and silicon-di-oxide (SiO2) surfaces via a layer-by-layer (LBL) deposition method. The isolated CNCs were monodis-persed and exhibited a length of 200-300 nm and a diameter of 10-20 nm, a negative zetapotential (34-39 mV) over a wide pH range, and high stability in water at various concentrations. The multi-layered structure, adsorbed mass, conformational changes, and anticoagulant activity of sequen-tially deposited anionic (sulfated) CNCs and cationic polyethyleneimine (PEI) on the surfaces of cellulose and SiO2 by LBL deposition were investigated using a quartz crystal microbalance tech-nique. The organization and surface features (i.e., morphology, thickness, wettability) of CNCs ad-sorbed on the surfaces of PEI deposited at different ionic strengths (50-300 mM) of sodium chloride were analysed in detail by profilometry layer-thickness, atomic force microscopy and contact angle measurements. Compared to cellulose (control sample), the total coagulation time and plasma deposition were increased and decreased, respectively, for multilayers of PEI/CNCs. This study should provide new possibilities to fabricate and tailor the physicochemical properties of multilayer films from polysaccharide-based nanocrystals for various biomedical applications.Acknowledgments: The authors acknowledge Volker Ribitsch (retired) from the University of Graz/Austria for his support and valuable discussion for this manuscript. The authors also acknowledge the financial support from the Slovenian National Research Agency ARRS (Grant No. J4-1764).Scopu

Investigation of physical and mechanical properties of nano-pulverized cellulose nanofiber preform sheets for CNF thermoset nanocomposites application

autho

Epitaxial Growth of Yb₂O₃ Buffer Layers on Biaxially Textured-Ni (100) Substrates by Sol-Gel Process

In order to develop an alternative buffer layer architecture using the sol-gel process to produce YBCO (YBa2Cu307+) coated conductors, Yb203 has been chosen as the candidate material. Buffer layers of fi03 were epitaxkdly grown on biaxially textured-Ni (100) substrates by the sol gel process for the first time. The ~03 precursor solution was prepared from an alkoxide sol-gel route in 2-xnetho~ethanol and was deposited on textured-Ni (100) substrates by either spin coating or dip coating methods. The amorphous film was then processed at 1160oC under flowing (96%)MH2(4%) gas mixture for one hour. The fi03 iihn exhibited a strong c-axis orientation on the Ni (100) substrates. The phi and omega scans indicated good in plane and out of plane orientations. The X-ray (222) pde figure showed a cube-on-cube epitaxy. High current YBCO films were grown on the Y&03 sol-gel buffered-Ni substrates

Demonstration of High Current Density YBCO Coated Conductors on RE₂O₃-Buffered Ni Substrates with Two New Alternative Architectures

In continuation of our effort to develop single buffer layer architectures for YBCO (YBa2Cu3O7-g) coated tape conductors, we have studied RE2O3 (RE = Y, and rare earths) as candidate materials. Three types of crystal structures including the preferred cubic phase are known for the rare earth oxides. High quality simple cubic RE2O3 buffer layers were grown epitaxiahy on {100} textured Ni substrates using both reactive evaporation and sol-gel processing. Detailed X-ray studies have shown that the Y2O3, Eu2O3, Gd2O3, and Yb2O3 were grown with a single epitaxial orientation. SEM micrographs indicated that both e-beam and sol-gel grown films were dense, continuous and crack free. High Jc YBCO films were grown on RE2O3-buffered Ni substrates with sputtered cap layers. Two new alternative buffer layer architectures were developed. A high Jc of 1.8 MA/cm2 at 77 K and self-field was obtained on YBCO films with a layer sequence of YBCO (pulsed laser deposition)/Yb2O3 (sputtered)/Y2O3 (e-beam)/Ni. Also, a high Jc of over 1 MA/cm2 at 77 K and self-field was obtained on YBCO films with a layer sequence of YBCO (ex-situ BaF2 process)/CeO2 (sputtered)YSZ sputtered)/RE2O3 (sol-gel or e-beam)Ni. The performance of sol-gel grown buffers approached the quality of e-beam grown buffers