High Internal Phase Emulsion Stabilization through Restricted Interdrop Fusion across Water Drainage Channels

Abstract

This study introduces a promising approach to stabilize high internal phase emulsions (HIPEs) in which droplets are enveloped by octadecane (C18)-grafted bacterial cellulose nanofibers (BCNFdiC18), which are mainly surrounded by carboxylate anions and hydrophobically modified with C18 alkyl chains. For this purpose, BCNFdiC18, in which two octadecyl chains were grafted onto each of several cellulose unit rings on 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidized BCNFs, was fabricated using the Schiff base reaction. The wettability of BCNFdiC18 was adjusted by controlling the amount of the grafted C18 alkyl chain. Interfacial rheological analysis revealed that BCNFdiC18 enhanced the membrane modulus at the oil–water interface. We figured out that such a resilient interfacial membrane substantially prevented interdrop fusion across the water drainage channel formed between the jammed oil droplets, which was confirmed theoretically using the modified Stefan–Reynolds equation. These findings highlight that the use of surfactants in the form of nanofibers to form a rigid interfacial film plays a key role in hindering the interfusion of the internal phase and the collapse of the emulsion, which is essential for HIPE stabilization.

Ultralight, Robust, Thermal Insulating Silica Nanolace Aerogels Derived from Pickering Emulsion Templates

“…For Pickering emulsion stabilization, we attempted to enhance the adsorption of ASNLs at the O/W interface by manipulating their surface wettability, which is achieved by controlling the relative surface introduction of amine groups and C 6 alkyl chains. As a model for the SiNL surface, we observed the contact angle of the surface-modified silicon wafer with HTMS at 55 mM and varied the grafting amount of APTES. ,− When the APTES was grafted at 20 mM, it exhibited a contact angle of 107.9°, and after grafting above 35 mM, the contact angle did not change significantly above 120° due to the saturation of the C6 alkyl chain (Figure a). Moreover, these results were consistent with the increased ζ-potential relative to the concentration of APTES grafted onto SiNLs (Figure b).…”

Shear‐Responsive Sol–Gel Transition of Phase Change Material Emulsions for an Injectable Thermal Insulation Platform

“…First, we employed an octadecane (C18)grafted BCNF (BCNF diC18 ) surfactant with carboxylate groups on their surface to stabilize n-hexadecane (Figure S1, Supporting Information). [38] Subsequently, a Zn ion-coordinated PA membrane was armored onto the surface of BCNF diC18 through elec-trostatic interactions between the carboxylate anions and Zn ions. We expected this MOM layer to promote interdrop attraction created by the ion bridge between neighboring PA molecules, resulting in a viscoelastic PCM emulsion fluid.…”