Self-assembled monolayers and polymer brushes

Self-assembled monolayers and polymer brushed can be used to tailor surface-chemistry, thus, surface energies, charges and polarities. We apply such molecular surface modifications to tailor interfacial energies and guide soft matter-solid interactions.

Self-assembled monolayers (SAMs) consisting of molecules with a head group, a spacer and a tail group arrange themselves on a surface with the head group being covalently bonded to the surface while spacer and tail group stretch away from the surface. By this, a close-packed monolayer of parallel molecules forms. The tail group builds the new interface towards air and thus determines the surface properties.

We use octadecyltrichlorosilane (OTS) to create SAMs on silicon surfaces to change their wetting properties from hydrophilic to hydrophobic and mercaptopropyltrimethoxysilane (MPTMS) to tailor the reactivity of silica surfaces. Creating SAMs of MPTMS results in a surface termination with thiol group, which can bind e.g. Au nanoparticles covalently.

Polymer brushes are for instance used to render surfaces ’neutral‘ for block copolymer lithography purposes. We create random-copolmyer brushes on oxide (SiO2, TiO2) surfaces and analyse these brush layers by ellipsometry, contact angle measurements, AFM and TEM.