Nanostructure and shape control in polymer-ceramic hybrids from poly(ethylene oxide)-block-poly(hexyl methacrylate) and aluminosilicates derived from them

The present study describes the use of poly-(ethylene oxide)-block-poly(hexyl methacrylate) diblock copolymers (PEO-b-PHMA) as structure-directing agents for the synthesis of nanostructured polymer-inorganic hybrid materials from (3-glycidylpropyl)trimethoxysilane and aluminium sec-butoxide as precursors and organic, volatile solvents. Four different morphologies, i.e., inorganic spheres, cylinders, lamellae, and organic cylinders in an inorganic matrix, are obtained confirmed by a combination of small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The composites are further characterized by differential scanning calorimetry (DSC) and solid-state C-13, Si-29, and Al-27 NMR. It is demonstrated that the change in the hydrophobic block from polyisoprene (PI) to poly(hexyl methacrylate) (PHMA) has no significant effect on the local structure of the inorganic rich phase. By the dissolution of the composites rich in poly(hexyl methacrylate), nano-particles of different shapes, i.e., spheres, cylinders, and lamellae, are obtained as demonstrated by atomic force microscopy (AFM) and TEM. Finally, calcination of composites with the inverse hexagonal structure at elevated temperatures up to 600 degreesC results in nanostructured aluminosilicates that retain their structured as evidenced through a combination of SAXS and TEM. The study opens pathways towards tailoring filler-matrix interactions in model nanocomposites and builds the bases for the preparation of composites from multiblock copolymers with polyisoprene (PI), poly(ethylene oxide) (PEO), and poly(hexyl methacrylate) (PHMA) as building blocks. Bright field TEM micrograph of composite T55/1 with inverse hexagonal morphology after calcination.