STABILITY AND MODIFICATION OF POLYGLUTAMATE LANGMUIR-BLODGETT BILAYER FILMS

Langmuir-Blodgett bilayers of a polyglutamate (PG) statistical copolymer have been investigated using atomic force microscopy (AFM) and X-ray reflectivity. PG ordered bilayer films on silicon surfaces possess an 'expanded' thickness of 4.12 +/- 0.05 nm and an average roughness of 0.7 +/- 0.2 nm. Possibilities for surface modification by the AFM tip were explored. Formation of an 'abrasion'' surface morphology was related to a stick-slip mode of the AFM tip movement. Using the AFM tip, several surface modifications were investigated: fabrication of large (several hundreds of nanometers) and small (several nanometers) holes; ''writing'' of grooves of predictable geometry; fabrication of holes of single layer and bilayer depth; cleaning of the surface and fabrication of holes inside this new area. The anisotropic mechanical properties of the PG bilayer were probed and attributed to orientation of the PG backbones along the dipping direction. The dynamic behavior of the surface changes were observed as well.