title: Photon Harvesting in Sunscreen-Based Functional Nanoparticles.
abstract: The ultraviolet light component in the solar spectrum is known to cause several harmful effects, such as allergy, skin ageing, and skin cancer. Thus, current research attention has been paid to the design and fundamental understanding of sunscreen-based materials. One of the most abundantly used sunscreen molecules is Avobenzone (AB), which exhibits two tautomers. Here, we highlight the preparation of spherically shaped nanoparticles from the sunscreen molecule AB as well as from sunscreen-molecule-encapsulated polymer nanoparticles in aqueous media and study their fundamental photophysical properties by steady-state and time-resolved spectroscopy. Steady-state studies confirm that the AB molecule is in the keto and enol forms in tetrahydrofuran, whereas the enol form is stable in the case of both AB nanoparticles and AB-encapsulated poly(methyl methacrylate) (PMMA) nanoparticles. Thus, the keto-enol transformation of AB molecules is restricted to a nanoenvironment. An enhancement of photostability in both the nanoparticle and PMMA-encapsulated forms under UV light irradiation is observed. The efficient excited energy transfer (60 %) from AB to porphyrin molecules opens up further prospects in potential applications as light-harvesting systems.
authors.affiliation: Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata, 700 032, India.|Department of Chemistry, Vivekananda Mahavidyalaya, Burdwan, Sripally, Burdwan-, 713103, West Bengal, India.
authors.forename: Sadananda
authors.initials: S
authors.lastname: Mandal
authors.affiliation: Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata, 700 032, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Bera
authors.affiliation: Unilever R & D Bangalore, 64, Main Road, Whitefield, Bangalore, 560066, India.
authors.forename: Somnath
authors.initials: S
authors.lastname: Das
authors.affiliation: Bio-organic Division, Bhabha Atomic Research Centre, Mumbai-, 400 085, India.
authors.forename: Sandip K
authors.initials: SK
authors.lastname: Nayak
authors.affiliation: Unilever R & D Bangalore, 64, Main Road, Whitefield, Bangalore, 560066, India. amitava.pramanik@unilever.com.
authors.forename: Amitava
authors.initials: A
authors.lastname: Pramanik
authors.affiliation: Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata, 700 032, India. msap@iacs.res.in.
authors.forename: Amitava
authors.initials: A
authors.lastname: Patra
mesh_terms: D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects; D017785:Photons; D019904:Polymethyl Methacrylate / Q000737:chemistry* / Q000528:radiation effects; D011427:Propiophenones / Q000737:chemistry* / Q000528:radiation effects*; D013473:Sunscreening Agents / Q000737:chemistry* / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D011427:Propiophenones; D013473:Sunscreening Agents; D019904:Polymethyl Methacrylate; C049935:avobenzone
keywords: nanoparticles; photostability; steady state; sunscreen molecules; time-resolved spectroscopy