Chemico-physical and functional properties of inorganic sunscreens in cosmetic products.
Synopsis This paper reports preliminary results of a study carried out on liquid crystal emulsions added to three different inorganic sunscreens: ultrafine zinc oxide, ultrafine titanium dioxide (inorganic-treated) and ultrafine titanium dioxide (organic-treated hydrophobically). The aim of the work was to investigate the influence of chemico-physical properties of inorganic sunscreens on the microstructure of cosmetic emulsions. The study was carried out using three different techniques: rheological measurements performed in dynamic conditions, to study the homogeneity of samples and their structural features; dispersion of powders in emulsions by optical microscopy and SEM/EDX analysis; and functionality of emulsions by UV spectroscopy, with adhesive tape as substrate. Results show that the different chemico-physical properties of the micropigments lead to different interactions with emulsion components; these interactions may affect the functionality and microstructure of the whole system, with loss of stability.
Semenzato
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Centro di Cosmetologia Chimica dell'Università di Padova, Dipartimento di Scienze, Farmaceutiche, Via Marzolo 5, 35131 Padova, Italy.
Dall'aglio
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C
Boscarini
G M
GM
Ongaro
A
A
Bettero
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A
Sangalli
M E
ME
Brunetta
F
F