title: Synthesis of Upconverting Hydrogel Nanocomposites Using Thiol-Ene Click Chemistry: Template for the Formation of Dendrimer-Like Gold Nanoparticle Assemblies.
abstract: The synthesis of upconverting hydrogel nanocomposites by base-catalyzed thiol-ene click reaction between 10-undecenoic acid capped Yb(3+)/Er(3+)-doped NaYF4 nanoparticles and pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) as tetrathiol monomer is reported. This synthetic strategy for nanocomposite gels is quite different from works where usually the preformed gels are mixed with the nanoparticles. Developing nanocomposites by surface modification of capping ligands would allow tuning and controlling of the separation of the nanoparticles inside the gel network. The hydrogel nanocomposites prepared by thiol-ene click reaction show strong enhancement in luminescence intensity compared to 10-undecenoic acid-capped Yb(3+)/Er(3+)-doped NaYF4 nanoparticles through the upconversion process (under 980 nm laser excitation). The hydrogel nanocomposites display strong swelling characteristics in water resulting in porous structures. Interestingly, the resulting nanocomposite gels act as templates for the synthesis of dendrimer-like Au nanostructures when HAuCl4 is reduced in the presence of the nanocomposite gels.
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Kolkata, Mohanpur, West Bengal 741252 (India).
authors.forename: Brahmaiah
authors.initials: B
authors.lastname: Meesaragandla
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Kolkata, Mohanpur, West Bengal 741252 (India). mvenkataramanan@yahoo.com.
authors.forename: Venkataramanan
authors.initials: V
authors.lastname: Mahalingam
keywords: click chemistry; fluorides; gold; nanostructures; upconversion