Single-molecular hybrid nano-cylinders: Attaching polyhedral oligomeric silsesquioxane covalently to poly(glycidyl methacrylate) cylindrical brushes

We present the preparation of novel single-molecular hybrid nano-cylinders by covalently attaching a monothiol-functionalized polyhedral silsesquioxane (POSS-SH) to poly(glycidyl methacrylate) (PGMA) cylindrical brushes. Grafting of GMA from a long poly-initiator poly(2-(2-bromoisobutyryloxy)ethyl methacrylate) (PBIEM) via ATRP was first carried out. Gel permeation chromatography (GPC), 1H NMR, dynamic light scattering (DLS), static light scattering (SLS) and atomic force microscopy (AFM) measurements confirmed the well-defined worm-like structures of the PGMA brushes. Then POSS-SH was covalently linked to PGMA brushes by reaction with about 19% of the epoxy groups. The successful preparation of the PGMA-POSS hybrid brush was demonstrated by Fourier-transform infrared spectroscopy (FTIR), DLS, SLS, energy dispersive X-ray spectroscopy (EDX) and thermogravimetric analysis (TGA) measurements. An increase of the length and diameter of the brushes was shown by AFM and non-stained transmission microscopy (TEM) measurements. Residual SiO2 after pyrolysis of the PGMA-POSS hybrid brush in air displayed interesting cylindrical network structures.