Time-Resolved SAXS Study of Polarity- and Surfactant-Controlled Superlattice Transformations of Oleate-Capped Nanocubes During Solvent Removal

• Structural transformations and lattice expansion of oleate-capped iron oxide nanocube superlattices are studied by time-resolved small-angle X-ray scattering (SAXS) during solvent removal. The combination of conductor-like screening model for real solvents (COSMO-RS) theory with computational fluid dynamics (CFD) modeling provides information on the solvent composition and polarity during droplet evaporation. Evaporation-driven poor-solvent enrichment in the presence of free oleic acid results in the formation of superlattices with a tilted face-centered cubic (fcc) structure when the polarity reaches its maximum. The tilted fcc lattice expands subsequently during the removal of the poor solvent and eventually transforms to a regular simple cubic (sc) lattice during the final evaporation stage when only free oleic acid remains. Comparative studies show that both the increase in polarity as the poor solvent is enriched and the presence of a sufficient amount of added oleic acid is required to promote the formation of structurally diverse superlattices with large domain sizes. © 2022 The Authors. 

Subject headings

NATURVETENSKAP  -- Fysik -- Annan fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Other Physics Topics (hsv//eng)

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Keyword

anisotropic nanoparticles

small angle X-ray scattering

superlattice transformation

time-dependent measurements

Computation theory

Computational fluid dynamics

Evaporation

Iron oxides

Oleic acid

Solvents

Nanocubes

Poor solvents

Solvent removal

Structural transformation

Surfactant-controlled

Time dependent measurements

Time-resolved

X ray scattering

Publication and Content Type

ref (subject category)

art (subject category)