Hybrid Hairy Two-Dimensional Nanostructures with Tunable Morphologies by Inclusion Crystallization of Lead Bromide Complexes with Polystyrene- block -poly(ethylene oxide)

High Resolution Image Download MS PowerPoint Slide We report the formation of hybrid hairy nanostructures composed of polystyrene- block -poly(ethylene oxide) (PS- b -PEO) and lead bromide (PbBr 2 ) complexes in 1,3,5-trimethylbenzene (TMB). In this system, TMB acts as a selective solvent (good for the PS block and bad for the PEO block) while serving as a nonsolvent for PbBr 2 . Although PbBr 2 is insoluble in neat TMB, its complexation with PS- b -PEO promotes the formation of the [PbBr 3 ] − and [PbBr 4 ] 2– complexes. These complexes coordinate with the ether groups of the PEO block, forming host–guest interactions that drive the inclusion crystallization of two-dimensional (2D) hybrid nanostructures, including irregular nanosheets and polygonal nanoplates. The morphology of these nanostructures strongly depends on the PS- b -PEO/PbBr 2 weight ratio. Higher ratios (20/100 and 20/200) favor irregular nanosheets, while lower ratios (20/10) favor polygonal nanoplates. Structural analysis reveals that the irregular nanosheets adopt an orthorhombic Cmca lattice ( a = 23.53 Å, b = 4.20 Å, c = 33.22 Å), whereas the polygonal nanoplates exhibit a hexagonal P 6 mm lattice ( a hex = 13.954 Å, γ = 120°). Both types of 2D structures are decorated with ultrasmall PbBr 2 nanoparticles encapsulated by PS- b -PEO chains. The PEO blocks coordinate to nanoparticle surfaces, while PS blocks swell in the TMB. This synergistic process integrates PbBr 2 complexation, host–guest coordination, inclusion crystallization, and block copolymer-mediated nanoparticle assembly. In spin-coated films, polygonal nanoplates preferentially adopt edge-on orientations, while irregular nanosheets lie flat-on. These findings offer insights into block copolymer templating of 2D organic–inorganic hybrid nanostructures.