Katarzyna Michocka

Effect of Sodium Chloride on the Surface and Wetting Properties of Aqueous Solutions of Cocamidopropyl Betaine

Surfactants are important ingredients of personal care products and household products. The main characteristic of these compounds is to decrease the surface tension of solvent and resulting many properties such as contact angle, foam properties etc. The coexistence of other ingredients in the product may affect the properties of surfactants. One of the main components contained in almost every personal care and household product is sodium chloride. The main aim of this work was to determine the effect of this salt on some surface and usage properties of cocamidopropyl betaine (CAPB). From our experiments it was shown that the effect of added sodium chloride in the aqueous solutions of CAPB on the properties is the opposite to the one described in the literature for cationic and anionic surfactants, i.e., CMC increases with increasing ionic strength, foam height decreases with increasing salt concentration. Our investigation showed that sodium chloride makes worse the properties of the CAPB solutions examined in this work.

The Antimicrobial Properties of Selected Oils Used as Cosmetics Compounds

Cosmetic vegetable oils for centuries have been objects of interest as ingredients of natural personal care products. Nowadays the trend for coming back to nature has caused their increased popularity in the preparation of natural cosmetics, soaps, and fragrance oils. Th e aim of the study was to evaluate the antimicrobial properties of 18 selected cold pressed cosmetic oils towards human pathogens. Th e antagonistic activity of cosmetic oils was assayed by the disc diff usion method. Indicator microorganisms chosen for the study were the bacteria Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and yeasts Candida albicans. Th e conducted research showed that selected cosmetic oils demonstrate diff erent antagonistic eff ects towards indicator microorganisms. Th e highest antibacterial activity was found in tamanu seed oil. Th is cosmetic oil decreased the growth of S. aureus, S. epidermidis and P. aeruginosa to a signifi cant level. Wheat germ oil inhibited the growth of S. epidermidis and P. aeruginosa. Th e oil of the black cumin seed was showed antibacterial activity towards S. aureus. None of the other tested cosmetics oils exhibited antimicrobial activity towards selected microorganisms as well as none of them was eff ective enough to inhibit the growth of E. coli and C. albicans. Th e antibacterial properties of the selected oils depended on their type as well as tested microorganism.