Group of Polymer Membranes and Bioanalogous Interfaces

Head: Zbynek Pientka , PhD
(phone +420-296 809 247, e-mail pientka@imc.cas.cz)

Research

The aim is focused on the determination of application potential of new materials, technologies for polymer membrane preparation, and methods for characterization of membrane structure and properties. Nanotechnologies are developed making possible controlled assembling of biological and synthetic macromolecules into functional nanostructures.

• New proton exchange membranes for hydrogen and direct methanol fuel cells have been developed. Homogeneous membranes of sulfonated poly(phenylene oxide) performed well in hydrogen fuel cells.. They were highly proton-conductive and showed good thermal and oxidative stabilities. However, they were highly permeable to methanol which makes their use in direct methanol fuel cells difficult. In this respect, they are similar to commercial, very expensive perfluorinated Nafion membranes. Heterogeneous membranes based on small particles of sulfonated poly(phenylene oxide) or sulfonated poly(phenylene sulfide) dispersed in a matrix of linear polyolefin were also highly-proton conductive, but, at the same time, they showed extremely low permeability to methanol. This makes them candidates for use in direct methanol fuel cells.
• Membrane process for biohydrogen (a gas mixture formed in fermentation by some microorganisms) separation has been designed and implemented
• Diffusivity, permeability and solubility of gases and vapours in new polymeric materials were measured. Collected transport properties allow to predict the separation efficiency of corresponding membranes. A new method of gas transport measurements in swollen material was developed. It is useful for characterization of various materials in real conditions, e.g., by oxygen permeability in hydrogel contact lenses, barrier properties of packing materials, and permeability of vapours in pervaporation membranes. High-performance membranes for CO₂/CH₄ separations have been developed recently. They found utilization in landfill gas processing. Membrane investigations also comprise preparation of ultrathin layers as well as characterization and morphology studies of heterogeneous structures.
• Essential factors controlling the formation and stability of molecular multilayers composed by layer-by-layer deposition of biological and synthetic macromolecules have been investigated within the nanobiotechnology program.. The gained knowledge has been utilized for the preparation of organized assemblies for three areas of practical applications: (a) Immunosensors or magnetic particles for immunoanalysis and separation have been prepared by coating surfaces of surface plasmon resonance (SPR) sensors or polymer magnetic beads with assemblies containing monoclonal or polyclonal antibodies against various molecular analytes of medical interest and foodborn bacterial pathogens. (b) Bloodcompatible materials have been obtained by coating surfaces of medical polymers with albumin and albumin-heparin multilayers. (c) Cell-seeding supports for tissue engineering have been prepared by coating polymer surfaces with assemblies of cell-adhesive biomolecules, such as, collagen IV, gelatin, laminin, fibronectin, and poly(L-lysine).
• Two-dimensional nanostructures from fibrin fibres and three-dimensional fibrin networks of designed nanometer morphology for cell therapy have been prepared by successive deposition and activation of fibrinogen and controlled fibrin preparation.
• The formation of the interfacial assemblies and their properties in aqueous media are studied in situ using FTIR multiintrnal reflection spetroscopy and SPR. The morphology of nanostructures is studied in aqueous media by AFM.