Self-Assembly and Photopolymerization of Diacetylene Molecules on Surface of Magnetite Nanoparticles

Abstract

An amphiphilic diacetylene compound was deposited on the surface of nano sized magnetite particles (Fe 3 O 4 ) using a self-assembly method. The diacetylene molecular assembly formed on the surface of nanoparticle was subjected to photopolymerization. This resulted in the formation of a polymeric assembly on the surface of the nanoparticles in which the adjacent diacetylene molecules were connected through conjugated covalent networks. The presence of immobilized polymer species on the surface of nanoparticles is expected to protect them from agglomeration and ripening, thereby stabilizing their physical properties. In this work, Fe 3 O 4 nanoparticles were prepared by chemical coprecipitation method and the diacetylene molecule 10,12-pentacosadiynoic acid (PCDA) was anchored to the surface of Fe 3 O 4 nanoparticles through its carboxylate head group. Irradiation of UV light on the nanoparticles containing immobilized diacetylenes resulted in the formation of a polymeric assembly. Presence of diacetylene molecules on the surface of nanoparticles was confirmed by X-ray photoelectron spectroscopy and FT-IR measurements. Photopolymerization of the diacetylene assembly was detected by UV-Visible spectroscopy. Magnetic properties of the nanoparticles coated with polymeric assembly were investigated with SQUID and magnetic hysteresis showed superparamagnetic behaviors. The results put forward a simple and effective method for achieving polymer coating on the surface of magnetic nanoparticle.

Phase Change Ultrasound Contrast Agents with a Photopolymerized Diacetylene Shell

“…PCDA monomers can form vesicles with a bilayer arrangement in aqueous solutions with the polar heads oriented toward the water interface. − In the case of PFC NDs, possible shell forming self-assembly of the PCDA units can result in a monolayer, triple layer or more, as described in Scheme S2 of the Supporting Information. Counting NDs with an average diameter larger than 800 nm, detectable by bright field microscopy, the average surface occupied per PCDA molecules, i.e.…”

“…Reznik et al reported on 400 nm PFC encapsulating droplets which expand into MBs with a diameter of 1.4 μm after 1 ms and 5.6 μm after 1s from ADV . Sheeran et al have shown that there is a significant difference in the size increase between degassed and undegassed samples upon ADV, suggesting that undegassed samples tend to increase more in size over time, excluding a coalescence effect between MBs. An increase of about 25 times of the particle diameter, after ADV, is reported for droplets of PFP stabilized in a suspension of saline containing bovine serum albumin.…”

Silica covered stannic oxide nanoparticles—an easily prepared robust substrate for optical sensors

“…The density of the magnetite core is 5.15 g cm −3 , which increases the overall particle density, making the particles easier to separate by centrifugation. Although the magnetite greatly assists with the separation, magnetite nanoparticles are not a promising substrate for optical sensors due to their black color and therefore, the presence of an absorption peak in the visible region [14]. Due to this, using the magnetite nanoparticles for this purpose would result in difficult, if not impossible analysis/visualization of the optical signal.…”