Study of Convergence of Substrate Thickness in Melt-Grown Single-Co-Crystals Having Hydrophobic-Hydrophilic Surface Morphology

The surfaces of poly(ethylene glycol) (PEG) single crystals have been designed by homo and copolymer self-assembling. A single-co-crystal is a crystalline specimen with a uniform structure having two or more crystalline component. By fabrication of single-co-crystals from melt of homopolymer and crystalline-amorphous diblock copolymers through self-seeding approach, a micronic homogeneous film of polymer chains was prepared on the silicon wafer. Co-continuous surface morphologies were developable on poly(ethylene glycol)-b-polystyrene (PEG-b- PS)/polyethylene glycol (PEG) and poly(ethylene glycol)-b-poly(methyl methacrylate) (PEG-b- PMMA)/(PEG) single-cocrystals. The characteristics of different morphologies were detectable by atomic force microscopy (AFM), electron diffraction patterns (ED) of transmission electron microscopy (TEM), and interface distribution function (IDF) of small angle x-ray scattering (SAXS) instruments. Convergence of PEG substrate thickness was intensified from molecular weight of 5000 to 100000 g/mol. Finally, this height convergenge reached to 50.57 nm forPEG100000/PEG5000-b-PS14800 single-co-crystals at crystallization temperature of 30 ºC (from 152.68 nm for homo-PEG100000 to 102.11 nm in single-co-crystal).