Search Results (10)

Fragrance is an odorous, volatile substance. Conventionally, encapsulation is performed to improve the preservation and persistence of smells. Typical methods of fragrance encapsulation include interfacial polymerization and the sol-gel method. However, there are issues such as low encapsulation efficiency and difficulty in controlling capsule size and shell thickness. Recently, a method for generating water-in-oil-water (W/O/W)-type microcapsules using microfluidic technology was reported. This made it possible to achieve high encapsulation efficiency and excellent control of the capsule diameter and shell dimensions. However, because this method involves a preliminary dispersion process for fragrance, the production process is more complicated than that of microcapsules using general microfluidic technology. In this study, we used a method for generating oil-in-water-in-oil (O/W/O)-type microcapsules in a microchannel with partially controlled wettability and achieved the generation of monodisperse fragrance-containing microcapsules with a hydrophilic polymer shell without the need for a preliminary dispersion process. Full article

Fabric softeners are formulated to enhance textile softness and impart a pleasant scent. One of the most efficient technologies for controlled fragrance delivery onto fabrics involves encapsulating scent molecules in polymer capsules. Here, we investigate the adsorption of anionic fragrance capsules on cotton fabrics with the goal of reducing the reliance on palm-oil-derived surfactants. First, we employ 200 nm cellulose nanocrystals (CNC) as a reliable model for cotton fibers. CNC enables us to explore interactions among various softener components, including surfactants, guar biopolymers, and fragrances, using physical chemistry techniques applied to bulk dispersions. The primary objective is to elucidate the role of surfactant vesicles, the primary ingredient in textile conditioners, in the association between fragrance capsules and cotton. Secondly, we examine the influence of biopolymers present in a newly developed environmentally friendly softener on this association. Our findings demonstrate that anionic fragrance capsules are deposited onto cotton microfibers in the presence of either cationic surfactants or guar biopolymers, driven by electrostatic interactions. Scanning electron microscopy confirms capsule adsorption on textile fibers when these cationic ingredients are present. Understanding the interaction mechanisms between fragrance capsules and cotton fabrics, as well as the roles played by other softener components, can facilitate the design of more efficient and sustainable formulations. Full article

Microcapsules are small particles that can effectively protect a core material from degradation. Microcapsules with double capsule walls can improve stability and reduce breakage due to the fact that the physical and chemical properties of double-walled materials can complement each other, thus enhancing the quality and applicability of a microcapsule. Microcapsules can achieve controlled release of core materials by using a temperature-sensitive wall material. In this research, gelatin was used as the inner wall material for these double-walled microcapsules. The outer wall material was a composite material prepared by the reaction of a hydroxyl group in gum arabic with an amino group in N-isopropylacrylamide (NIPAM) in the presence of N, N’-methylene bisacrylamide (BIS), while lavender fragrance oil served as the core material. A complex coalescence method was used for the preparation of microcapsules with double capsule walls. The effects of different proportions of gum arabic to NIPAM on the core loading, microcapsule yield and thermal stability of microcapsules were studied in detail. Additionally, the stability of these fragrance microcapsules with double capsule walls in different solvents and pH values was evaluated. The sustained release properties and mechanism of cotton fabrics treated with prepared fragrance microcapsules were investigated. The results show that the microcapsules prepared with a 10:1 ratio of NIPAM to gum arabic have good temperature responsiveness. Therefore, clothing treated with microcapsules with temperature-sensitive wall materials can ensure that the human body has a fresh and pleasant smell in the case of perspiring in summer. Full article

Microencapsulation can improve the thermal stability of a fragrance, and composite wall materials are one way to further improve the thermal stability of microcapsules. This paper presents a facile approach for cotton fabric coatings by using cellulose/silica hybrid microcapsules. Lavender fragrance oil-loaded cellulose/silica hybrid microcapsules were one-step synthesized via emulsion solvent diffusion. The prepared microcapsules were found to be spherical in shape with a particle size distribution between 500 to 1000 nm. Due to the slow releasing of lavender fragrance oil in the capsules, the fragrance loss rate of (3-aminopropyl)triethoxysilane (APTES)-, triethoxy(3-glycidyloxypropyl)silane (GPTES)-, and (3-aercaptopropyl)trie-thoxysilane (MPTES)- modified cellulose/silica hybrid microcapsules are 25.2%, 35.1%, and 16.7% after six hours at 120 °C. E-nose and gas chromatography–mass spectrometry (GCMS) studies found that the fragranced cotton fabrics had good retention of characteristic aromas. It provides the basis for the application of the heating treatment of cotton fabrics in sterilization, bleaching, printing, and other processes. Full article

Flavours and fragrances are volatile compounds of large interest for different applications. Due to their high tendency of evaporation and, in most cases, poor chemical stability, these compounds need to be encapsulated for handling and industrial processing. Encapsulation, indeed, resulted in being effective at overcoming the main concerns related to volatile compound manipulation, and several industrial products contain flavours and fragrances in an encapsulated form for the final usage of customers. Although several organic or inorganic materials have been investigated for the production of coated micro- or nanosystems intended for the encapsulation of fragrances and flavours, polymeric coating, leading to the formation of micro- or nanocapsules with a core-shell architecture, as well as a molecular inclusion complexation with cyclodextrins, are still the most used. The present review aims to summarise the recent literature about the encapsulation of fragrances and flavours into polymeric micro- or nanocapsules or inclusion complexes with cyclodextrins, with a focus on methods for micro/nanoencapsulation and applications in the different technological fields, including the textile, cosmetic, food and paper industries. Full article

Microencapsulation is a technique that is increasingly used to encapsulate fragrances. It offers a valuable method to protect aromas against degradation in technological processes and during storage, which extends the usefulness of the aroma in the production and processing of food products. The aim of this research was to develop a microencapsulation method of gamma-decalactone, a cyclic ester with the scent of peach, which is used as a food additive. The carrier used for microencapsulation was an emulsion consisting of rapeseed oil, maltodextrin and gum Arabic. In this work, optimization of the carrier composition was performed in order to obtain a stable emulsion. The effect of inlet air temperature (80 °C, 180 °C) during spray drying on the powder quality parameters was then analyzed. In the final stage, the gamma-decalactone content in the obtained powders was evaluated. The results showed that emulsions based on colza oil and gum Arabic are a good carrier for the microencapsulation of gamma-decalactone. The use of high pressure during homogenization results in better fragmentation and homogenization of the emulsion. Drying at a higher inlet air temperature (180 °C) contributes to a more efficient microencapsulation process in that more aroma is encapsulated inside the capsules with less adhering to their surface. Full article

Thymol and the corresponding brominated derivatives constitute important biological active molecules as antibacterial, antioxidant, antifungal, and antiparasitic agents. However, their application is often limited, because their pronounced fragrance, their poor solubility in water, and their high volatility. The encapsulation of different thymol derivatives into biocompatible lignin-microcapsules is presented as a synergy-delivering remedy. The adoption of lignosulfonate as an encapsulating material possessing relevant antioxidant activity, as well as general biocompatibility allows for the development of new materials that are suitable for the application in various fields, especially cosmesis. To this purpose, lignin microcapsules containing thymol, 4-bromothymol, 2,4-dibromothymol, and the corresponding O-methylated derivatives have been efficiently prepared through a sustainable ultrasonication procedure. Actives could be efficiently encapsulated with efficiencies of up to 50%. To evaluate the applicability of such systems for topical purposes, controlled release experiments have been performed in acetate buffer at pH 5.4, to simulate skin pH: all of the capsules show a slow release of actives, which is strongly determined by their inherent lipophilicity. Full article

Perfume encapsulates are widely used in commercial products to control the kinetic release of odorant molecules, increase storage stability and/or improve deposition on different substrates. In most of the cases, they consist of core-shell polymeric microcapsules that contain fragrance molecules. A current challenge is to design and produce polymeric materials for encapsulation that are both resistant and non-persistent. The selection of such eco-friendly formulations is linked to a deep understanding of the polymeric material used for encapsulation and its biodegradation profile. To collect this information, pure samples of capsule shells are needed. In this article we present an innovative quantification method for residual volatiles based on pyrolysis-GC-MS to enable validation of sample quality prior to further testing. The presented analytical method also led to the development of a robust and comprehensive purification protocol for polymers from commercial samples. Standard techniques are not suited for this kind of measurement due to the non-covalent embedding of volatiles in the 3D structure of the polymers. We demonstrated the confounding impact of residual volatiles on the estimated biodegradability of fragrance encapsulates. Full article

In this study we explored the implementation of the vapor induced phase separation (VIPS) to produce cellulose acetate microcapsules for the encapsulation of a complex mix of fragrances. VIPS is a technique used for membrane preparation, but barely mentioned for microencapsulation. We compared the products from VIPS and a more common microencapsulation process, the immersion precipitation technique (IPS). The capsules prepared via VIPS show a core-shell structure with a thin polymeric shell surrounding the internally empty space, conversely to those produced via IPS, showing an incomplete spherical morphology. This can be attributed to a better control of the precipitation rate of the encapsulation material in the non-solvent thanks to the longer exposition time to the vapor. The activity and encapsulation efficiency of the capsules, obtained through TGA analysis, reached a maximum of ≈75% and ≈90%, respectively. Moreover, a growing trend between the initial active concentration and the encapsulation efficiency is noticed. Full article

A significant amount of academic and industrial research efforts are devoted to the encapsulation of active substances within micro- or nanocarriers. The ultimate goal of core–shell systems is the protection of the encapsulated substance from the environment, and its controlled and targeted release. This can be accomplished by employing “stimuli-responsive” materials as constituents of the capsule shell. Among a wide range of factors that induce the release of the core material, we focus herein on the light stimulus. In polymers, this feature can be achieved introducing a photo-sensitive segment, whose activation leads to either rupture or modification of the diffusive properties of the capsule shell, allowing the delivery of the encapsulated material. Micro- and nano-encapsulation techniques are constantly spreading towards wider application fields, and many different active molecules have been encapsulated, such as additives for food-packaging, pesticides, dyes, pharmaceutics, fragrances and flavors or cosmetics. Herein, a review on the latest and most challenging polymer-based micro- and nano-sized hollow carriers exhibiting a light-responsive release behavior is presented. A special focus is put on systems activated by wavelengths less harmful for living organisms (mainly in the ultraviolet, visible and infrared range), as well as on different preparation techniques, namely liposomes, self-assembly, layer-by-layer, and interfacial polymerization. Full article