Molecular basis for solvent dependent morphologies observed on electrosprayed surfaces

Abstract

We study the causes of the observed tunable hydrophobicity of poly(styrene-co-perfluoroalkyl ethylacrylate) electrosprayed in THF, DMF, and THF : DMF (1 : 1) solvents. Under the assumption that equilibrium morphologies in the solvent significantly affect the patterns observed on electrosprayed surfaces, we use atomistic and coarse-grained simulations supported by dynamic light scattering (DLS) experiments to focus on the parameters that affect the resulting morphology of superhydrophobic electrosprayed beads. The differing equilibrium chain size distributions in these solvents examined by DLS are corroborated by chain dimensions obtained via molecular dynamics simulations. Mesoscopic morphologies monitored by dissipative particle dynamics simulations explain experimental observations; in particular, the preference of the polymer for THF over DMF in the binary mixture rationalizes the dual scale roughness driven by stable microphase separation. Drying phenomena that affect resultant dual-scale roughness are described in three stages, each interpreted by concentration dependent diffusion and surface mass transfer coefficients of the solvents. Irrespective of the presence of polar groups in the structure, a conflict between the lower-boiling point solvent adhering to the polymer and the less volatile solvent abundant in the bulk leads to perfectly hydrophobic surfaces.

Enhanced Performance of Polymeric 19F MRI Contrast Agents through Incorporation of Highly Water-Soluble Monomer MSEA

“…This indicates that the population giving the second peak at over 100 nm in the intensity-based distribution is small. The second peak in the intensity-based distribution can be attributed to agglomerated polymer chains due to lack of swelling in water . It is also observed that although all the PMSEA–PTFEA polymers have comparable molecular weights, the size of these polymers in aqueous solution increased with increasing fluorine content.…”

Controlling Homogenous Spherulitic Crystallization for High‐Efficiency Planar Perovskite Solar Cells Fabricated under Ambient High‐Humidity Conditions

“…THF : THF displays an anomaly compared to all other antisolvents. The precursor solution does not precipitate but disperses in THF, which is likely caused by the molecular repulsion between THF and DMF . As a result, crystal growth is stunted with THF treatment, which leads to the smallest grain size as well as smallest crystallite size for THF‐treated films samples (Figure a and Table ).…”

Electrosprayed Molybdenum Trioxide Aqueous Solution and Its Application in Organic Photovoltaic Cells

“…In this process, MoO 3 aqueous droplets are continuously deposited, but the low vapor pressure of the additive solvent causes organic solvent to remain on the substrate after depositing the droplet. E. Ozden-Yenigun demonstrated that the drying process of the thin film was influenced by (i) the boundary layer resistance to solvent transport into vapor and (ii) the internal diffusion resistance to solvent loss [46] . In addition, the slow evaporation speed of the droplet occurs the main resistance to solvent loss, resulting in the free movement of solvent in the droplet.…”