(2)Ĭolloidal silica, produced in a multistep sol-gel process, has received particular attention in the last decade as a nanouller for polymer composites. When certain types of titanium dioxide particles are incorporated in the paint, super-hydrophilicity (due to photo-induced water adsorption) is combined with photocatalytic activity, promoting oxidative degradation of organic dirt. On super-hydrophilic coatings, on the other hand, high wettability promotes water sheeting that washes the surface effectively. Fluorinated polymers or additives are typically used for these applications. (1) In the former, liquid water forms spherical droplets that roll down the surface carrying dirt deposited on the surface. (1-5) This means that specific human intervention and/or use of cleaning agents is not necessary to maintain the original visual appearance of the applied paint.Ĭurrent applications for self-cleaning paints involve two types of approaches: super-hydrophobicity and super-hydrophilicity. Concerning the particular case of dirt pick-up, several works have been reported on the development of surfaces with self-cleaning character, i.e., low adhesion towards dirt particles and capability of being efficiently cleaned solely by exposure to natural actions like rainfall or solar radiation. Some relevant properties are low dirt pick-up, good color retention, and good chalking and crack resistances. Keywords Nanocomposite, Acrylic polymer, Self-cleaning coating, Aqueous dispersionįacade paints must provide an effective and robust protection of the substrate, while preserving its decorative properties under all weather conditions. The lower dirt pick-up was attributed to nanoroughness created by the nanosilica particles present in the film. Surface hardness measurements indicated no significant differences between the original and composite paint films. This self-cleaning performance remained unchanged after several dirt/washing cycles, during a 1-month period. Washing with running water further decreases dirt retention. This hybrid coating showed significantly lower dirt pick-up than the equivalent paint formulation without nanosilica additive, towards both organic and inorganic ashes. SEM imaging indicated good dispersion of silica within the polymer matrix. Abstract A nanodispersion of surface-functionalized fumed silica was incorporated into an acrylic paint formulation.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |