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Spinel Ferrites—A Future Boon to Nanotechnology- Based Therapies
Published in Nandakumar Kalarikkal, Sabu Thomas, Obey Koshy, Nanomaterials, 2018
R Sharath, Nagaraju Kottam, H Muktha, K Samrat, M. Chandraprabha, R Harikrishna, Bincy Rose Vergis
Spinel ferrites have been prepared by reverse micelle micro emulsion method. In this method, NPs synthesis involves preparation of aqueous solution of precursor material (nitrate salts) with addition of a surfactant (sodium dodecyl sulfate (SDS), cetrimonium bromide (CTAB), Triton-X 100, Tween 80, or polysorbate 80), and toluene to form a reverse micelles. This solution is then refluxed following removal of excess toluene through distillation; the resulting brown particles are then washed with water and ethanol to ensure that any excess surfactant is removed. The solution mixture is subjected to centrifugation and particles are collected. The sample is annealed at a ramping rate which results in a fine black powder. The size of the particles can be varied by adjusting the water to toluene ratios.
Carbon Based Supercapacitors
Published in Ling Bing Kong, Nanomaterials for Supercapacitors, 2017
Ling Bing Kong, Wenxiu Que, Lang Liu, Freddy Yin Chiang Boey, Zhichuan J. Xu, Kun Zhou, Sean Li, Tianshu Zhang, Chuanhu Wang
Commercial CVD grown MWCNTs with diameter of 10–12 nm and BET surface area of 250–300 m2·g−1 were refluxed with 9 M HNO3 for 24 hours for purification and carboxylation, followed by filtration and thorough washing with DI water. α-Fe2O3 nanospheres were derived from FeCl3·6H2O aqueous solution, with the presence of cetrimonium bromide (CTAB), which was heated to 100°C for 15 hours, followed by filtration, washing and drying. α-Fe2O3/MWCNT suspensions were prepared by dispersing MWCNTs in water with the aid of ultrasonication, which was then mixed with FeCl3·6H2O and CTAB, with weight ratios of α-Fe2O3 to MWCNT to be 60:1, 9:1, 3:1 and 1:1. Film electrodes were obtained by spraying suspensions of α-Fe2O3 and α-Fe2O3/MWCNT in ethanol with a concentration of 1 mg·mL−1 on Cu foils.
Proteins in Cosmetics
Published in E. Desmond Goddard, James V. Gruber, Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
E. Desmond Goddard, James V. Gruber
Finally, proteins are reported to be potential inhibitors of numerous preservatives commonly used in cosmetics (130). The mechanisms involved are various and not fully understood: the reactivity of amino groups and electrostatic interactions are both possible. Also, protein materials are generally good substrates for microbial growth and partial inactivation of the preservative system may be the result of the higher consumption of biocides needed to face an increased microbial proliferation. Formaldehyde intentionally used or liberated by relevant donor biocides is easily consumed by condensation with free amino groups of peptides. Protein hydrolysates, having a high percentage of reactive amines, are stronger inactivation agents than larger proteins, while large polypeptides may lose solubility by masking the few amino groups present into nonionizable derivatives. Quaternary preservatives such as benzalkonium chloride and cetrimonium bromide may be inactivated by electrostatic interaction with anionic peptides, and potential inhibition is also reported for phenols, phenoxyethanol, and isothiazolinones.
Wettability alteration of carbonate reservoir rock using amphoteric and cationic surfactants: Experimental investigation
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Yaser Souraki, Erfan Hosseini, Ali Yaghodous
Two surfactants, one new amphoteric and one cationic surfactant were used in this experimental study. Initial surfactant is HABSA which is the recognized amphoteric surfactant. HABSA formulation is (C16H33C6H3NH2SO3H) that shows, when it dissolves in water, it contains two charged groups of different sign at its head and a long alkyl tail. The second used surfactant was cetrimonium bromide ((C16H33)N(CH3)3Br, cetyl trimethyl ammonium bromide, CTAB) which is one of the components of the topical antiseptic cetrimide. Figure 1b shows surfactants. These surfactants were acquired from Merck Company. These surfactants were dissolved in water and their critical micelle concentration (CMC) were measured. Chemical structures of HABSA and CTAB are shown in Figure 1c–d.
Lubricating and physico-chemical properties of CI- 4 plus engine oil dispersed with surface modified multi-walled carbon nanotubes
Published in Tribology - Materials, Surfaces & Interfaces, 2018
V. Srinivas, Ch. Kodanda Rama Rao, N. Mohan Rao
As the MWCNTs tend to agglomerate and form large particles clusters, it is required to modify the surface of MWCNTS with a surfactant to create stearic repulsions between individual nanotubes. To stabilise the nano particles in the liquid medium, two kinds of surfactants: SPAN 80 and Cetrimonium bromide (CTAB) are used to modify the surface of MWCNTs during the preparation of oil. Span80 is a nonionic surfactant with a hydrophilic-lipophilic balance of 4·6 which is ideally suitable for oils. Cetrimonium bromide (CTAB) is a quaternary ammonium nonionic surfactant. It adsorbs on the surface of nanoparticles reducing their surface energy thereby preventing aggregation and settling of nanoparticles.