The spatial distribution of charged spherical colloids when used as stabilizers of phytantriol-based emulsified microemulsions (EME, L2 symmetry group) is investigated. The coverage of the lipid-based mesophases by the colloids is monitored using small-angle neutron scattering (SANS) in contrast matching conditions and visualized using cryogenic transmission electron microscopy (cryo-TEM) imaging. The results demonstrate that, despite the stability of the emulsion droplets, very few colloids are ever found on the droplets. The stability of the EMEs is suggested to arise from the very slow ripening rates combined with punctual repulsion against coalescence from the isolated charged colloids on the bigger droplet surfaces. We show the possibility of creating a dense cover around the droplets by partially hydrophobizing the colloids by adsorbing a cationic surfactant on their surface. This opens up the possibilities for further modulation of the colloidal coverage in these systems. This is an interesting route for the design of new Colloid-ISAsome assemblies in which dense protective armors could be advantageous such as controlled delivery.
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http://dx.doi.org/10.1016/j.jcis.2015.01.007 | DOI Listing |
Huan Jing Ke Xue
January 2025
Beijing Key Laboratory of Urban Atmospheric Volatile Organic Compounds Pollution Control and Application, Beijing Municipal Research Institute of Eco-Environmental Protection, Beijing 100037, China.
To analyze the emission characteristics of VOCs from pesticide use sources in Beijing, the distribution of commonly used pesticides and dosage forms in Beijing was obtained through on-site research, and the VOC content of pesticides in different dosage forms was examined using laboratory testing methods. The emission factors of pesticide VOCs for localized dosage forms in Beijing were established, an inventory of pesticide use source VOCs was compiled, and the spatial and temporal distribution characteristics of pesticide use source VOCs were analyzed. The results indicated that ① Pesticide dosage forms were the main factors affecting the emission of VOCs from pesticides, and when accounting for VOC emissions from pesticide sources, it is necessary to know the types of pesticides and active ingredients in the target area and obtain information on pesticide dosage forms simultaneously.
View Article and Find Full Text PDFPharmaceutics
October 2024
Department of Bioengineering, iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
Oils and lipids help make water-insoluble drugs soluble by dispersing them in an aqueous medium with the help of a surfactant and enabling their absorption across the gut barrier. The emergence of microemulsions (thermodynamically stable), nanoemulsions (kinetically stable), and self-emulsifying drug delivery systems added unique characteristics that make them suitable for prolonged storage and controlled release. In the 1990s, solid-phase lipids were introduced to reduce drug leakage from nanoparticles and prolong drug release.
View Article and Find Full Text PDFLangmuir
November 2024
Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China.
pH-switchable surfactant-based microemulsions (SBMEs) are those that can switch reversibly between a monophasic state and a fully phase-separated state under the alternation of acids and bases, which is rarely reported. By using an equimolar mixture of sodium dodecyl sulfate and N,N-dimethyldodecylamine (SDS-CA) as a pH-switchable surfactant, a pH-switchable SDS-CA-based microemulsion (SDS-CA-ME) has been fabricated for the first time. The main principles of the reversible switching are the reversible destruction/formation of the emulsifier, SDS-CA--butanol, film at the oil-water interface due to the alternating protonation/deprotonation of CA caused by acids and bases.
View Article and Find Full Text PDFJ Colloid Interface Sci
February 2025
Interfaces, Confinement, Matériaux et Nanostructures (ICMN), CNRS-Université d'Orléans, UMR 7374, 1b rue de la Férollerie, CS 40059, 45071 Orléans Cedex 2, France.
Hypothesis: Mesophase dispersions are promising colloids for removing micropollutants from water. We hypothesized that the complex internal nanostructure and tunable lipid/water interface amounts play a crucial role in absorbed quantities. Modifications in interfacial organization within the particles while trapping the micropollutant is assumed.
View Article and Find Full Text PDFACS Phys Chem Au
September 2024
Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
The versatility of environmentally benign and inexpensive deep eutectic solvents (DESs) lies in their widely varying physicochemical properties. Depending on its constituents, a DES may be highly polar or nonpolar in nature. This offers an enticing possibility of formation of novel nonaqueous microemulsions (MEs).
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