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No. 4
Vol. 42 , No. 2, pp. 102–109, 2008
A novel water‐based sunscreen gel using a polymer – zinc oxide composite
Author(s) -
Takahashi Eiji,
Oikawa Tetsuya,
Iyanagi Hirokazu,
Mohri Kunihiko,
Nakamae Katsuhiko
Publication year - 2009
Publication title -
international journal of cosmetic science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 62
eISSN - 1468-2494
pISSN - 0142-5463
DOI - 10.1111/j.1468-2494.2008.00466_4.x
Subject(s) - zinc , composite number , polymer , chemical engineering , materials science , coating , chemistry , nanotechnology , composite material , metallurgy , engineering
Conventional sunscreen products generally must strike a compromise between efficacy and product feel; the hydrophobic ingredients that provide the sun protection generally impart an unpleasant, greasy feel and the greater the SPF rating, the worse the greasy feel. We tested an idea that a water‐based sunscreen gel formulation containing inorganic UV absorbers would provide an effective way to address these problems. Our goal was to find a way to disperse inorganic sunscreen materials in water and to incorporate them into a water‐based gel which would provide a more pleasant product feel. After extensive research we discovered a polymer‐zinc oxide composite (P‐ZnO) with high UV protective effect and high dispersibility in water. In dried powdered form, P‐ZnO can be easily dispersed in water. P‐ZnO makes it possible to formulate a gel‐type sunscreen, which is not possible using commercially available inorganic powders. The composite size of P‐ZnO is about 500 nm and its structure consists of a dense aggregate of nano‐ZnO having a size distribution in the 5–10 nm range and amorphous layers of poly acrylic acid coating zinc oxide to control the particle growth, block surface activity and prevent aggregation. The water‐based P‐ZnO sunscreen gel offers UV protection comparable to conventional products in a delivery vehicle that is much more pleasant to use.