Search results for "Pickering emulsion"
showing 8 items of 18 documents
Halloysite based geopolymers filled with wax microparticles as sustainable building materials with enhanced thermo-mechanical performances
2022
This work proposes a novel protocol for the fabrication of halloysite based geopolymers filled with beeswax microparticles obtained from Pickering emulsions. The actual filling of the microwax into the geopolymers has been demonstrated by using several techniques, including thermal analyses, spectroscopies, microscopies and contact angle experiments. According to the morphological and structural investigations, microwax spherical particles (diameter ranging between ca. 3 and 5 μm) have been homogeneously dispersed within the geopolymeric network conferring excellent properties to the hybrid geopolymers in terms of mechanical performances and heat storage capacity although their low content …
Pickering Emulsions Stabilized by Halloysite Nanotubes: From General Aspects to Technological Applications
2022
Besides surfactants, which decrease the interfacial tension between two immiscible liquids, also interfacially active particles can successfully stabilize an emulsion system by attaching at the liquid–liquid interface. The preparation of the resulting Pickering emulsions has been so far investigated starting from the study of the interactions arising between the dispersed droplets and the stabilizers, till the application of these systems in a wide range of different fields. This work is intended to provide an overall overview about the development of Pickering emulsions by considering the most general aspects and scanning the diverse types of solid stabilizers. Among them, Halloysite nanot…
Hydroxypropyl Cellulose Films Filled with Halloysite Nanotubes/Wax Hybrid Microspheres
2021
The design of novel nanocomposite films based on hydroxypropyl cellulose (HPC) and wax/halloysite hybrid microspheres has been reported. In particular, we first prepared wax/clay Pickering emulsions which were characterized by thermogravimetric analysis and microscopy. SEM images allowed more detailed insights on the nanotubes disposition at the wax/water interface, acting as an outer stabilizing shell. Therefore, the cellulosic biopolymer was added, and it was found that HPC enhances the colloidal stability of the particles, preventing their coalescence and sedimentation. The preparation of the composite films was carried out by the solvent casting method, which enabled the development of …
Magnetically enhanced polymer-supported ceria nanocatalysts for the hydration of nitriles.
2020
The heterogeneous catalysis of the hydration of nitriles to amides is a process of great industrial relevance in which cerium(IV) oxide (also referred to as ceria) has shown an outstanding catalytic performance. The use of non-supported ceria nanoparticles is related to difficulties in the purification of the product and the recovery and recyclability of the catalyst. Therefore, in this work, ceria nanoparticles are supported on a polymer matrix either by synthesizing polymer particles by so-called Pickering miniemulsions while using ceria nanoparticles as emulsion stabilizers or, as a comparison, by in-situ crystallization on preformed polymer particles. The former strategy presents signif…
Nanoscale hybrid silica/polymer Janus particles with a double-responsive hemicorona
2015
Abstract We report a versatile large-scale synthesis strategy for hybrid Janus nanoparticles with a silica core and a unilaterally attached polymer corona in a size range below 100 nm. The stimuli-responsive behavior of these nanoparticles with a poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) hemicorona is investigated. The synthesis is based on a modified version of the Pickering emulsion polymerization technique in combination with surface-initiated atom transfer radical polymerization (ATRP) in a “grafting from” approach. In a first step, poly(vinyl acetate) (PVAc) latex particles are prepared via Pickering emulsion polymerization. Colloidal stability is provided by 30 nm silica nan…
Colloidal stability and self-assembling behavior of nanoclays
2020
Abstract Currently, nanoclays are attracting the attention of a wide part of the scientific community, due to some of their most peculiar features that make them good candidates for applications in different fields. In light of this, some strategies can be pursued in order to obtain stable colloidal dispersions of nanoclays with the aim to improve their features and to expand their use. Hence, this chapter presents an overview on the structural and morphological characteristics, the physico-chemical properties and the main approaches that are taken into account for the preparation of homogeneous suspensions of Halloysite, Imogolite and Laponite in both aqueous and apolar solvent media. In p…
Pickering Emulsion Gels Based on Halloysite Nanotubes and Ionic Biopolymers: Properties and Cleaning Action on Marble Surface
2019
We have fabricated ecocompatible Pickering emulsions based on halloysite nanotubes and ionic biopolymers (chitosan and pectin) from renewable resources. The effect of pectin and chitosan on the Pickering emulsion was investigated by direct visualization of the oil droplets and by the thermodynamic characterization at the interface. Pectin enhances the Pickering emulsion stability, while a phase separation and nonhomogeneous gel was observed in the presence of chitosan. We have demonstrated that the Pickering emulsion in a pectin based gel phase is suitable for wax layer removal from a marble surface. A controlled cleaning is achieved by tuning the contact time between the gel and the marble…
The Essential Oil of
2019
Many chemicals used nowadays for the preservation of cultural heritage pose a risk to both human health and the environment. Thus, it is desirable to find new and eco-friendly biocides that can replace the synthetic ones. In this regard, plant essential oils represent effective alternatives to synthetic substances for the preservation of historical monuments. Thymbra capitata (syn. Thymus capitatus) is a medicinal and aromatic plant growing in the Mediterranean area and endowed with important pharmacological properties related to its essential oil. Among them, the antimicrobial ones make the T. capitata essential oil an ideal candidate for industrial applications; for instance, as biocide f…