Nanostructured surfaces
Molecular assemblage and characterization of functional polymeric brushes on amorphous metal surfaces
O. Izhyk1, O. Balaban1, O. Hertsyk2, M. Holovchuk3, K. Volianiuk1, N. Mitina1, A. Zaichenko1
1Lviv Polytechnic National University. St.Bandera str., 12, Lviv – 79013, Ukraine.
E-mail: oleh.b.izhyk@lpnu.ua
2Department of Physical and Colloid Chemistry, Ivan Franko National University of Lviv, Cyril and Methodius str., 6, Lviv – 79005, Ukraine.
3Karpenko Physico-Mechanical Institute of NAS of Ukraine, Naukova str., 5, Lviv–79060, Ukraine.
The tendency of polymeric surfactants to self-organization into ordered and semi-ordered aggregates, hierarchical assemblies, networks, brushes and others nanostructures in liquids and on surfaces provides purposeful construction of functional materials for patterning, self-healing, corrosion inhibition, energy storage, drug carrying. Controlled synthesis of a new generation of surface-active oligomers containing a set of reactive side or/and terminal groups opens perspective ways for molecular assemblage of nanoscale functional brushes including formation of self-ordered sandwich structures on surfaces of various natures: glass, ceramics, metals. Two functional oligomers containing side peroxide, acetate (pyrrolidone) and anchor phosphate or carboxyl groups synthesized in our lab were used as precursors for attachment and formation of the brushes on the sheets of amorphous metal alloys. Oligomer anchor phosphate or carboxyl groups formed coordinated or, possibly, simultaneously salt bonds with metallic surface. Free acetate or pyrrolidone fragments form not only complex of weak bonds with the plate surface but also influence on interactions between attached polymer brushes and define hydrophilic or hydrophobic characteristics of the modified surface. An availability of radical forming peroxide-containing units in attached polymer brushes provides possibility of grafting hydrophobic or hydrophilic functional chains via polymerization initiated from the surface, so called “grafting from». Contact angle measurements demonstrate the transformation of highly hydrophobic surface of non-modified (75 -105 ) to highly hydrophilic surface of modified flat plate (30 ) in a result of attachment of functional oligomer surfactant molecules. However, an availability of the sites possessing higher value of contact angle (80 ) on the surface of modified metal sheet was revealed. This can be explained, in our opinion, by the interaction of attached polymer brushes leading to formation of crystalline structures. The SEM study confirms the suggestion.