Surface Treatment of Broad-Spectrum Ultraviolet Light Shielding Titania/Zinc Oxide Composites and Their Applications in Sunscreens

Abstract

Nano-titanium oxide (TiO 2 ) and zinc oxide (ZnO) are widely used in sunscreen products, but many shortcomings for these both oxides still exist. In this paper, the hydrolysis of tetraethyl orthosilicate (TEOS) in ethanol solution was used to deposit inorganic silica nano-coating on the surface of TiO 2 /ZnO composite, followed by grafting by organosilane. The as-prepared products were characterized by XRD, FTIR, TG and TEM. In addition, Zeta potential, color difference test, dissolution experiments of zinc ions and water contact angle tests were used to characterize the effect of inorganic silica coating and organosilane grafting. Subsequently, the modified TiO 2 /ZnO composites were applied into the sunscreen formulation and the properties of the as-prepared emulsions were evaluated by the distribution analysis of the particle size, acceleration test and ultraviolet transmittance analyzer. The results showed that the sunscreen emulsion prepared by the TiO 2 /ZnO composite has better sun protection performance and stability than the emulsion prepared by the mixture of TiO 2 and ZnO.

Nanostructured ZnO and CuI Thin Films on Poly(Ethylene Terephthalate) Tapes for UV-Shielding Applications

“…In the SILAR process, one growth cycle included following three steps: (1) immersing of the substrate into cationic precursor for 10 s; (2) its immersing into anionic precursor, namely into hot (90 C) water for 10 s; (3) rinsing of a flexible substrate in a separate H2O beaker at room temperature for 5 s to remove loosely bound particles. The thickness of the obtained ZnO and ZnO:In films on PET substrates (t in the 0.1-3.8 m range) was determined gravimetrically, taking for the t calculation the bulk ZnO density of 5.61 g/cm 3 . As seen from Table 1, three SILAR modes differ from each other by the film thickness through an adjusting the number of SILAR cycles, by the presence or absence of In in the films, and by the application or not of the initial step for a creation of a bonding seed layer to ensure an adhesion of zinc oxide film with PET.…”

“…According to [1][2][3][4][5][6], since ultraviolet (UV) radiation triggers the formation of free radicals, the long-term exposure of human skin to UV radiation can result in health issues, such as aging, DNA damage, skin reddening, acne, and even skin cancer. UV light also has degradation effects on various materials, such as polymers, dyes, pigments and semiconductor devices [6].…”

“…UV light also has degradation effects on various materials, such as polymers, dyes, pigments and semiconductor devices [6]. Therefore, interest in the creation of light and flexible shields with variable shapes, which are capable of providing protection from solar UV, is particularly due to the need to reduce the risk of skin cancer and to prevent skin injury associated with UV exposure [1][2][3][4][5][6][7][8][9]. Extensive research efforts were focused on the development of UV shielding material, which may be efficient for UV protective coating [1][2][3][4][5][6][7][8][9], especially in the wavelength () range 290-400 nm (terrestrial UV part of the solar spectrum, namely 95 % UVA (320-400 nm range) and 5 % UVB (290-320 nm range)).…”

“…Therefore, interest in the creation of light and flexible shields with variable shapes, which are capable of providing protection from solar UV, is particularly due to the need to reduce the risk of skin cancer and to prevent skin injury associated with UV exposure [1][2][3][4][5][6][7][8][9]. Extensive research efforts were focused on the development of UV shielding material, which may be efficient for UV protective coating [1][2][3][4][5][6][7][8][9], especially in the wavelength () range 290-400 nm (terrestrial UV part of the solar spectrum, namely 95 % UVA (320-400 nm range) and 5 % UVB (290-320 nm range)). Generally, modern materials for sun protection contain nanoparticles or nanostructured layers of wide band gap semiconductors (mainly titanium dioxide (TiO2) or zinc oxide (ZnO)), whose large surface area to-volume ratio significantly increases the effectiveness to block UV radiation when compared to bulk materials [1][2][3][4][5][6][7].…”

“…Extensive research efforts were focused on the development of UV shielding material, which may be efficient for UV protective coating [1][2][3][4][5][6][7][8][9], especially in the wavelength () range 290-400 nm (terrestrial UV part of the solar spectrum, namely 95 % UVA (320-400 nm range) and 5 % UVB (290-320 nm range)). Generally, modern materials for sun protection contain nanoparticles or nanostructured layers of wide band gap semiconductors (mainly titanium dioxide (TiO2) or zinc oxide (ZnO)), whose large surface area to-volume ratio significantly increases the effectiveness to block UV radiation when compared to bulk materials [1][2][3][4][5][6][7]. Among them, the best choices for UV protection are nanostructured thin ZnO films [1,4] or indium doped ZnO:In films [1], hierarchical ZnO nanostructures [8], ZnO quantum dots [9], ZnO-polystyrene nanocomposite films [6], ZnO quantum dots/sodium carboxymethyl-cellulose nanocomposite polymer films [2], and fibrous ZnO/polyvinyl alcohol composite membranes [5].…”