Abstract
AbstractCooperative self‐assembly (co‐assembly) of diblock copolymers (DBCs) and inorganic precursors that takes inspiration from the rich phase separation behavior of DBCs can enable the realization of a broad spectrum of functional nanostructures with the desired sizes. In a DBC assisted sol–gel chemistry approach with polystyrene‐block‐poly(ethylene oxide) and ZnO, hybrid films are formed with slot‐die coating. Pure DBC films are printed as control. In situ grazing‐incidence small‐angle X‐ray scattering measurements are performed to investigate the self‐assembly and co‐assembly process during the film formation. Combining complementary ex situ characterizations, several distinct regimes are differentiated to describe the morphological transformations from the initially solvent‐dispersed to the ultimately solidified films. The comparison of the assembly pathway evidences that the key step in the establishment of the pure DBC film is the coalescence of spherical micelles toward cylindrical domains. Due to the presence of the phase‐selective precursor, the formation of cylindrical aggregates in the solution is crucial for the structural development of the hybrid film. The pre‐existing cylinders in the ink impede the domain growth of the hybrid film during the subsequent drying process. The precursor reduces the degree of order, prevents crystallization of the PEO block, and introduces additional length scales in the hybrid films.
Highlights
The precursor reduces the degree of order, prevents crystallization of the PEO block, and introduces additional length scales in the hybrid films
The amphiphilic diblock copolymers (DBCs) investigated in the present work has an average molecular weight of 20.5 and 8.0 kg mol−1 for hydrophobic PS and hydrophilic PEO blocks, respectively
The PS-b-PEO and PS-b-PEO/ZnO hybrid film,[62] the abovementioned in situ and ex situ studies probe the structural developments during slot-die coating
Summary
The amphiphilic DBC investigated in the present work has an average molecular weight of 20.5 and 8.0 kg mol−1 for hydrophobic PS and hydrophilic PEO blocks, respectively. The hard-sphere radius (rHS) and the volume fraction (vHS) of the correlated PS-b-PEO micelles are 20 ± 1 nm and 0.10 ± 0.01, respectively Such weak intermicellar interactions might originate from the semi-dilute concentration and increase the tendency to aggregation.[46,47] Matching only for a very narrow q range, the core–shell sphere model is invalid for fitting the SAXS data of the PS-b-PEO/ ZnO solution. The presence of ZnO precursor leads to a spherical-tocylindrical morphology transition, implying the occurrence of a 1D directional coalescence process of the ZnO-loaded PS-b-PEO micelles as a result of interfacial energy minimization (Figure 1d) Such information is of special importance as the co-assembly of the ZnO-loaded micelles in solution is a sophisticated process, wherein the hydrolyzed and condensed products of ZnO precursors would give rise to permanent Zn O covalent bonds with adjacent ZnO species on PEO moieties, and the formation of such an interconnected network is irreversible.[18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
