Using Grazing-Incidence Small-Angle Neutron Scattering to Study the Orientation of Block Copolymer Morphologies in Thin Films

• DOI: 10.1021/acs.macromol.2c02415
• Publication Date: 2023-03-15T12:46:19Z
• Authors: Mingqiu Hu; Xindi Li; William T. Heller; Wim Bras; Javid Rzayev; Thomas P. Russell
• Keywords: Grazing-incidence small-angle scattering; Polystyrene

We used grazing-incidence small-angle neutron scattering (GISANS) to probe the depth-dependent orientation of self-assembled morphologies block copolymers. A hydrophobic–hydrophobic copolymer, poly(solketal methacrylate)-block-polystyrene (PSM-b-PS), was synthesized and spin-coated into films tens nanometers in thickness where polymers adopted a disordered state. PSM-b-PS then hydrolyzed by exposing polymer thin film trifluoroacetic acid vapor or embedding photoacid generator during spin coating, followed exposure UV light. The hydrolysis converted copolymer hydrophilic–hydrophobic poly(glycerol monomethacrylate)-block-polystyrene (PGM-b-PS), significantly increasing segmental interaction parameter (χ) causing microphase separation GISANS study structure revealed that microphase-separated differed at polymer–air polymer–substrate interfaces. In regions lamellae were parallel interfaces, propagated from However, areas perpendicular did not persist with distance