Surface Properties of Colloidal Particles Affect Colloidal Self-Assembly in Evaporating Self-Lubricating Ternary Droplets

Abstract

In this work, we unravel the role of surface properties of colloidal particles on the formation of supraparticles (clusters of colloidal particles) in a colloidal Ouzo droplet. Self-lubricating colloidal Ouzo droplets are an efficient and simple approach to form supraparticles, overcoming the challenge of the coffee stain effect in situ . Supraparticles are an efficient route to high-performance materials in various fields, from catalysis to carriers for therapeutics. Yet, the role of the surface of colloidal particles in the formation of supraparticles using Ouzo droplets remains unknown. Therefore, we used silica particles as a model system and compared sterically stabilized versus electrostatically stabilized silica particles—positively and negatively charged. Additionally, we studied the effect of hydration. Hydrated negatively charged silica particles and sterically stabilized silica particles form supraparticles. Conversely, dehydrated negatively charged silica particles and positively charged amine-coated particles form flat film-like deposits. Notably, the assembly process is different for all the four types of particles. The surface modifications alter (a) the contact line motion of the Ouzo droplet and (b) the particle–oil and particle–substrate interactions. These alterations modify the particle accumulation at the various interfaces, which ultimately determines the shape of the final deposit. Thus, by modulating the surface properties of the colloidal particles, we can tune the shape of the final deposit, from a spheroidal supraparticle to a flat deposit. In the future, this approach can be used to tailor the supraparticles for applications such as optics and catalysis, where the shape affects the functionality.

Self-assembly of carbon nanodots induced by liquid–liquid phase separation in a surface microdroplet

“…When the ouzo effect is dominated during LLPS, oil droplets disperse in the continuous phase of water. C-dots absorb at the surface of oil micro/nanodroplets and stabilizes them, 46 leading to the formation of nanopores in the final carbon film (Fig. 7(b), o-Cdots).…”

“…The oil-to-particle ratio, size and surface properties of the assembled colloidal particles have been demonstrated to influence assembly structures. 45,46 Distinguished from previous reported assembled silica colloidal particles in the range of 10 to 1000 nm and graphenebased materials, 47,48 C-dots possess peculiar physical and structural features, including ultrasmall lateral dimension, a few layers of graphene sheets in-core structure and abundant surface functional groups. For example, surface oxides, such as carbonyl, carboxyl and hydroxyl groups, are the common species capping the carbon cores, enabling negative surface charge and high water solubility of C-dots.…”

“…The oil-to-particle ratio, size and surface properties of the assembled colloidal particles have been demonstrated to influence assembly structures. 45,46…”

Coacervate-mediated novel pancreatic cancer drug Aleuria Aurantia lectin delivery for augmented anticancer therapy

“…4 ) and fabricated mPEG-Coa as a AAL delivery carrier using polycation mPEG-PEAD and polyanion heparin. Here, PEGylation to polycations provides steric stability to the coacervate complex in a harsh environment [ 33 ] and their colloidal stability in aqueous conditions could be improved [ 14 , 15 ]. The enhanced stability of mPEG-Coa by PEGylation and its usefulness as an excellent growth factor carrier were demonstrated in our previous study, which suggested that the optimal range of PEG chain length for cation modification (MW 350) should be considered in ionic environments.…”

Formulation, Physico-chemical Evaluation and Comparative Stability Studies of Dillenia indica (pulp) based Antidandruff and Anti Hair Fall Cream with Marketed Brand

“…b) c) The beaker kept for 8 hrs in the humidity chamber at 60-70% relative humidity and temperature of 40°c ± 1°c. d) e) On removal from thermostat, oil separation was observed, if any [11].…”