Pickering Emulsion Gels Based on Halloysite Nanotubes and Ionic Biopolymers: Properties and Cleaning Action on Marble Surface

Abstract

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 surface. Due to its nonhomogeneous structure, chitosan-based gel does not show proper wax removal ability. This work opens up a new sustainable approach in preparing cleaning formulations for conservation of cultural heritage.

The Essential Oil of Thymbra capitata and its Application as A Biocide on Stone and Derived Surfaces

“…The emulsions are made up of fine particles that form a shell around the oil drop or water drop [57]. Water-in-oil (W/O) emulsions are widely used for different “soft” matter applications: pharmaceutical, food, personal care, agriculture and, as described in the present paper, in the restoration of cultural heritage [58,59,60]. Today, the use of Pickering particles as stabilizers for emulsions has received attention owing to their ability to adsorb irreversibly at the liquid/liquid interface [61,62].…”

Halloysite Nanotubes Coated by Chitosan for the Controlled Release of Khellin

“…In recent years, hybrid nanomaterials composed by biopolymers and inorganic nanoparticles have attracted growing interest within several fields, including biomedicine [ 1 , 2 , 3 , 4 , 5 ], pharmaceutics [ 6 , 7 , 8 , 9 , 10 ], food packaging [ 11 , 12 , 13 , 14 , 15 ], remediation [ 16 , 17 ] and cultural heritage [ 18 , 19 , 20 ]. As evidenced in a recent review [ 21 ], both ionic and non-ionic polysaccharides can be suitable polymers for the development of functional nanocomposites, with excellent performances in terms of thermal stability, barrier properties and mechanical behavior.…”

Bionanocomposite Films Containing Halloysite Nanotubes and Natural Antioxidants with Enhanced Performance and Durability as Promising Materials for Cultural Heritage Protection

“…The introduction of natural additives, such as reinforcement agents, cross-linking agents, and antioxidants, to single biopolymers or biopolymer blends favors the formulation of sustainable, eco-friendly, and non-toxic materials, having a beneficial effect on human health and the environment [ 27 ]. Among natural fillers, halloysite represents an emerging nanomaterial for the fabrication of bionanocomposites useful in numerous applications, such as food packaging [ 28 , 29 , 30 ], tissue engineering [ 31 , 32 , 33 , 34 ], delivery systems [ 35 , 36 , 37 , 38 ], photo-protection [ 39 , 40 ], and restoration [ 41 , 42 ]. As examples, the filling of pectin with halloysite nanotubes containing rosemary essential oil generated nanocomposite films with antimicrobial and antioxidative functionalities [ 28 ], while the combination of chitosan and halloysite loaded with diclofenac was exploited to fabricate tablets with controlled release properties [ 37 ].…”