Smartly designed photoreactive silica nanoparticles and their reactivity

Abstract

Monodisperse, colloidal silica nanoparticles (NPs) are being widely investigated due to a variety of applications in various fields of chemistry. Many works utilize incorporation of various functional groups to silica NPs for their further modifications. However, at present no benzophenone (BPh) or phenyl azide (PA) containing silica NPs exist. Upon UV irradiation BPh and PA form highly reactive species that react with any organic material. Here we present a convenient method for the preparation of novel hybrid photoreactive silica NPs (denoted as SiO 2 @photoreactive group) prepared by cocondensation of photoreactive organosilanes and tetraethyl orthosilicate (TEOS) to obtain SiO 2 @PA and SiO 2 @BPh NPs. The reactivity of these two types of silica NPs is compared to that of perfluorinated phenyl azide (PFPA) based SiO 2 NPs. The reactivity evaluation is carried out by the reaction of the three types of SiO 2 NPs with highly inert poly(2-chloro-paraxylelene) films. It is found that, in contrast to what is stated in the literature, PA is much more reactive than PFPA, when dealing with solid state photochemical reactions. Next, photoreactive silica NPs on polymer films are used as an intermediate functional phase for a second modification step using silane-based chemistry. A successful incorporation of amine functionality onto silica NPs is achieved by their reaction with 3-aminopropyltriethoxysilane (APTES) and is verified by fluorescence microscopy. This strategy provides a general and versatile route to efficient functionalization of silica by light.

Photochemically modified ATO NPs as conductive support of Pt electrocatalysts for proton exchange membrane fuel cells

“…Synthesis of 4-benzoyl-N-(3-(triethoxysilyl)propyl)benzamide (BPhTES) 4-benzoyl-N-(3-(triethoxysilyl)propyl)benzamide (BPhTES) was prepared using a procedure reported by our group (Peled et al 2011 Chemical BPh modification of ATO NPs Conductive ATO NPs were purchased from Inframat Advanced Materials LLC (99.95 %, Sb 2 O 3 :-SnO 2 = 10:90 (in weight), average particle size 10-20 nm, BET surface area 40-50 m 2 /g. The photoreactive benzophenone-silane BPhTES (327.00 mg, 0.76 mmol) were added to a dispersion of ATO NPs (150 mg) in EtOH (45 mL) under vigorous stirring for 24 h at 25°C.…”

Superhydrophobic durable coating based on UV‐photoreactive silica nanoparticles

“…Two basic features have to be combined to obtain durable superhydrophobicity. Thus, it is proposed to investigate the possibility to obtain robust hydrophobic topography by covalently binding silica NPs to a polymer base coating . Furthermore, a top layer of Fluor containing film will be studied for superhydrophobic chemistry.…”

“…BPhTES was synthesized as a first stage for the preparation of the hybrid photo reactive nanosilica particles . 4‐benzoylbenzoic acid (2.26 g, 10 mmol) and CDI (162 g, 10 mmol) were dissolved in dry THF (40 ml) in a two neck bottom flask equipped with drying tube.…”

“…BPhTES (0.76 mmol) was added to a solution of EtOH (45 ml) with TEOS (1.55 ml, 6.84 mmol) under vigorous stirring at RT . Then, water (2.75 ml) and NH 4 OH 28% (1.2 ml) were added to the reaction.…”

A simple one-step approach to the decoration of parylene C coatings using functional silica-based NPs

“…The first step, spin coating with hybrid SiO 2 NPs, revealed UVphotoreactive functional groups and was followed by UV irradiation. This type of UV-induced covalent modification of parylene C coatings by photoreactive hybrid SiO 2 NPs was found to be very stable by AFM (mechanical pushing of UV-anchored NPs on the surface of the film) and amenable to 2nd step chemical modifications [14].…”