In this investigation, polydimethylsiloxane (PDMS) ultrathin films are prepared on a variety of solid surfaces by a simple and fast spin coating method, and patterned with the natural biopolymer cellulose via lithographic methods. Two surface patterning methods are developed to create coatings of hydrophilic cellulose, regenerated from trimethylsilyl cellulose (TMSC) on the PDMS thin films. In method 1, spin coated TMSC films on PDMS are covered with a lithographic mask and exposed to vapors of hydrochloric acid, which results in spatially separated cellulose pads surrounded by TMSC. Subsequent selective dissolution of TMSC with organic solvents results in a direct anchoring of cellulose pads on the PDMS. In method 2, PDMS thin films covered with a lithographic mask are exposed to UV/ozone, spray coated with TMSC and regenerated to cellulose. The conversion of hydrophobic TMSC into hydrophilic cellulose coatings is confirmed by wettability and fluorescence measurements. The developed structures are highly transparent and stable in aqueous solutions (pH 3-9) and organic solvents. The surface properties of the polymer films are characterized using a quartz crystal microbalance with dissipation (QCM-D), ellipsometry, X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), contact angle and streaming potential measurements.
COBISS.SI-ID: 17607958
We are reporting on the preparation of organic/inorganic hybrid materials, namely cellulose fibrous networks with attached magnetic iron oxide particles. Research work was divided into three parts; pretreatment of regenerated cellulose fibres with an aim to activate their surface and enlarge the pore system, in order to enhance the adhesion of particles and allow their growth inside of fibres. Second part is concerned with the magnetite particles' synthesis and their properties; synthesis procedures were compared from the viewpoint of their suitability to be combined with cellulose fibres. Third part deals with the coating of fibres with magnetic iron oxide particles with different procedures. Effect of different pre-treatment procedures on fibres' supramolecular structure, enlargement of their pore system, surface potential and mechanical properties was investigated. Coating of fibres was carried out with an in situ formation of particles in presence of fibres, as well as with adsorption of particles from a pre-prepared dispersion. Composite magnetite-decorated cellulose fibres exhibit magnetic behaviour, degree of which is dependent on employed fibres' pre-treatment in combination with specific synthesis protocol for magnetite formation. Developed magnetic fibres are being considered as a shielding material for electromagnetic radiation.
COBISS.SI-ID: 16941846