New membrane technologies: Nanotube membranes for biotechnological applications and polyaniline films for corrosion inhibition

Chapter 1 provides background information on the template synthesis of nanomaterials. A description of the types of membranes used for template synthesis is given. Different chemistries that have been used to prepare template-synthesized structures are provided. Template synthesis has been used to prepare some important nanostructures. Polycarbonate membranes were used to prepare gold nanotubes using electroless gold template method. SiO₂ nano-test-tubes were made by dipping the alumina template membrane in the sol and heating. An introduction to conductive is presented here as well.; Chapter 2 describes the transport of DNA molecules through nanopore membranes. We are interested in how pore diameter of the membrane affects rate and selectivity of DNA transport of different size and charge. Commercially available microporous polycarbonate membrane filters were used. DNA chains can be driven through the nanopore via the electrokinetic transport processes of electrophoresis and electroolsmotic flow, as well as by diffusion. To our knowledge, there have been no quantitative studies of the relative importance of the electrokinetic and diffusive components for DNA transport in a nanopore system.; Chapter 3 describes a sol-gel template synthesis process that is used to produce silica nano-test-tubes within the pores of alumina templates. These silica nano-test-tubes are important because of the ease with which nearly any desired chemical or biochemical reagent can be covalently attached to their inside and outside surfaces. Inner and outer surfaces of the silica nano-test-tubes were functionalized using well-known silane chemistry. Green fluorescent silane was attached to the inner surfaces. The outer SiO ₂ nano-test-tube surfaces were antibody functionalized using aldehyde methoxysilane linker. One of our key long-range objective is to develop nanotube technology for delivering biomolecules (e.g., DNA) to living cells.; Chapter 4 focuses on the mechanism by which polyaniline (PANI) films passivate stainless steel surfaces in highly corrosive H₂SO ₄ solution. A variety of experimental methods including measurements of the open circuit potential, Auger depth profiling, and the scanning reference electrode technique (SRET) was used. These studies have shown that passivation is achieved because the oxidized and protically-doped emeraldine-salt form of PANI holds the potential of the underlying stainless steel electrode in the passive region. Because of this electrostatic mechanism of corrosion inhibition, the entire stainless steel surface does not have to be coated with PANI in order to achieve passivation.