Sodium dodecyl sulfate microaggregates with diversely developed surfaces: Formation from free microdroplets of colloidal suspension

Abstract

Unsupported drying of microdroplets of colloidal suspension can lead to the formation of complex micro-morphologies with quasi-spherical symmetry. Herein, drying of levitating microdroplets of suspension of SiO 2 nanospheres in diethylene glycol (DEG) with sodium dodecyl sulfate (SDS) is reported as a method for producing such microstructures with diversely developed surfaces. Dried products are "softlanded" on a substrate and studied with scanning electron microscopy (SEM). The smallest SDS/SiO 2 composites with the surface formed of crystallised SDS and interior filled with SiO2 nanospheres preserve the spherical symmetry. Larger microdroplets with higher initial mass fractions of SDS dry up to developed microstructures with SiO 2 nanospheres arranged in-between the crystallised SDS flakes which are similar to curved lobe cabbage leaves or "desert rose"-like structures with radially directed SDS crystals. Largest microdroplets with highest initial mass fractions of SDS formed doughnut-shaped micro-containers filled with aggregated SiO 2 nanospheres. In all these, SiO2 nanospheres served as a frame for the SDS crystallisation.

Deciphering the Kinetic Study of Sodium Dodecyl Sulfate on Ag Nanoparticle Synthesis Using Cassia siamea Flower Extract as a Reducing Agent

“…Sodium dodecyl sulfate (SDS) was considered as an anionic surfactant with the formula of C 12 H 25 NaSO 4 . SDS has been studied in various aspects of surface and colloid chemistry. , Subsequently, the nucleation stage of Ag NP synthesis got elongated, particularly beyond the cmc value of [SDS] considered. Also, complementary shapes were observed with the variation of [CSFE] and [SDS] with respect to each other.…”

Drying Kinetics and Particle Formation from Dilute Colloidal Suspensions in Aerosol Droplets

“…2 It is important to highlight that a high Peclet number is necessary but not sufficient for shell formation. [21][22][23][24] Process parameters such as the initial aerosol droplet parameters (droplet size, type of solvent, viscosity, concentration and size of the solid NPs) 8,[25][26][27][28] and the drying conditions (drying temperature and relative humidity) 8,11 can be optimized to achieve the required particle form for targeted applications. For example, in pharmaceutical applications, spherical, dense and crumpled dried powdered microparticles are produced via spray drying for capsules intended for oral drug administration and for deeper lung deposition respectively.…”

“…Process parameters such as the initial aerosol droplet parameters (droplet size, type of solvent, viscosity, concentration, and size of the solid NPs) ,− and the drying conditions (drying temperature and relative humidity) , can be optimized to achieve the required particle form for targeted applications. For example, in pharmaceutical applications, spherical, dense, and crumpled dried powdered microparticles are produced via spray drying for capsules intended for oral drug administration and for deeper lung deposition, respectively. , Experimentally, Iskandar et al used spray drying techniques to study the influence of initial droplet size, viscosity of the droplet, drying temperature, gas flow rate, and addition of surfactant on dried microparticle morphology.…”

Application of a linear electrodynamic quadrupole trap for production of nanoparticle aggregates from drying microdroplets of colloidal suspension

“…It allows the soft landing of the aggregated structures on a silicon substrate to enable further analysis [19]. Using the developed setup, we investigated the formation of highly ordered spherical aggregates of silica nanospheres [19] as well as the formation of sodium dodecyl sulfate (SDS) microaggregates, with and without silica nanospheres, showing diversely developed surfaces [20]. The microaggregates were formed by evaporation of colloidal suspension/solution droplets.…”

“…Using the LEQT, we studied the influence of addition of sodium dodecyl sulfate (SDS)/DEG solution to the colloidal suspension of silica on transient and dry patterns/structures obtained from such suspension/solution microdroplets. We have made an overview of the SDS/SiO 2 microproducts versus the initial concentration of SDS and recently reported on the mutual influence of the SDS-SiO 2 nanoparticles on the final dried composite microproducts [20]. The approximate proportion of DEG:SiO 2 :H 2 O = 1:10:15 was kept constant for the varying concentration of the SDS.…”