Fluoroalkyl-end-capped 2-acrylamido-2-methylpropanesulfonic acid cooligomers containing adamantyl segments were prepared by reaction of fluoroalkanoyl peroxide with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 3-hydroxy-1-adamantyl acrylate (Ad-HAc). These obtained fluorinated AMPS-Ad-HAc cooligomers were found to form nanometer-size-controlled fine particles not only in water but also in a large variety of traditionally organic solvents. In addition, these fluorinated cooligomeric nanoparticles showed a good dispersibility in these solvents. Interestingly, the size of these fluorinated nanoparticles is extremely sensitive to solvent changes, and an increase of the particle size was observed in the solvents, in which the dielectric constant is higher or lower. More interestingly, these fluorinated AMPS-Ad-HAc cooligomeric nanoparticles exhibited a lower critical solution temperature around 52 degrees C in an organic medium (tert-butyl alcohol).

Fluoroalkyl end-capped co-oligomeric nanoparticles, which were prepared by the reaction of fluoroalkanoyl peroxide with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 1-hydroxy-5-adamantylacrylate (Ad-HAc), were applied to the preparation of novel fluorinated co-oligomeric nanocomposite-encapsulated gold nanoparticles. These fluorinated gold nanocomposites were easily prepared by the reductions of gold ions with poly(methylhydrosiloxane) (PMHS) in the presence of the corresponding fluorinated nanoparticles and tri -n-octylamine (TOA) in 1,2-dichloroethane (DE) at room temperature. These fluorinated gold nanoparticles were isolated as wine-red powders and were found to exhibit good dispersibility in a variety of traditional organic solvents such as DE, methanol, and t-butyl alcohol to afford transparent wine-red solutions. The morphology and stability of these fluorinated co-oligomeic nanocomposite-encapsulated gold nanoparticles were characterized using transmission electron microscopy (TEM), dynamic light scattering measurements (DLS), and UV-vis spectroscopy. DLS measurements and UV-vis spectroscopy showed that these particles are nanometer-size-controlled very fine nanoparticles (185-218 nm) that exhibit a plasmon absorption band at around 530 nm. TEM images also showed that gold nanoparticles are tightly encapsulated into fluorinated co-oligomeric nanoparticle cores. Interestingly, these fluorinated co-oligomeric nanocomposites-encapsulated gold nanoparticles were found to afford linear arrays of these fluorinated nanoparticles with increases in the feed amounts of TOA. More interestingly, these fluorinated gold nanoparticles were able to afford the extremely red-shifted plasmon absorption band at around 960 nm.

CommunicationFluoroalkyl end-capped cooligomers that contain both oxime-blocked isocyanato and hydroxyadamantyl segments are prepared by the cooligomerization of fluoroalkanoyl peroxide with the corresponding monomers under mild conditions. This fluorinated cooligomer affords new cross-linked fluoroalkyl end-capped cooligomeric nanoparticles that contain adamantane segments by the deprotecting reaction of oxime-blocked isocyanato segments in cooligomers in excellent to moderate isolated yield. A variety of cross-linked fluoroalkyl end-capped cooligomeric nanoparticles that contain adamantane segments are also prepared by similar deprotecting reactions with this fluorinated cooligomer in the presence of adamantane-1,5-diol. Furthermore, we have prepared cross-linked fluoroalkyl end-capped cooligomers that contain oxime-blocked isocyanato segments by the use of 2-hydroxyethyl acrylate and poly(ethylene glycol)-containing methacrylate monomer as comonomers, respectively. However, the deprotecting reactions of the oxime-blocked isocyanato segments in the cooligomers do not afford the expected nanoparticles, and these cross-linked cooligomers are found to show a gelling characteristic. The thermal stability of these cross-linked fluorinated cooligomeric nanoparticles that contain adamantane segments increases significantly compared to that of the parent fluorinated cooligomer. More interestingly, the thermal stability of these cross-linked fluorinated nanoparticles is almost the same as that of the fluoroalkyl end-capped acrylic acid oligomer/SiO 2 nanocomposites (content of SiO 2 in composites: 70%). In addition, these cross-linked fluorinated nanoparticles have been applied to the surface modification of traditional organic polymers such as poly(methyl methacrylate) to exhibit a good oleophobicity imparted by fluorine on their surface.

New crosslinked fluoroalkyl end-capped co-oligomeric nanocomposite-encapsulated magnetic nanoparticles, prepared by the deprotecting reactions of corresponding fluorinated co-oligomers containing oxime-blocked segments in the presence of magnetic nanoparticles, were produced with nanometer-scale diameters (with diameters in the range of 154-192 nm). The nanoparticles exhibited good dispersibility in traditional organic solvents. They were applied as a surface modification to poly(methyl methacrylate), resulting in good oleophobicity imparted by the fluorine and magnetic properties arising from the encapsulated magnetic nanoparticles. Fluoroalkyl end-capped 2-acrylamido-2-methylpropanesulfonic acid co-oligomers containing adamantane segments form nanometer-sized controlled fine particles in methanol and can interact with magnetic nanoparticles to form fluorinated betaine-type co-oligomeric nanocomposite-encapsulated magnetic nanoparticles (with an average particle size of 25-183 nm). These fluorinated betaine-type nanocomposite-encapsulated magnetic nanoparticles exhibit the lower critical solution temperature (LCST) characteristic in organic media such as t-butyl alcohol and were found to effectively decrease the LCST through the encapsulation of magnetic nanoparticles in fluorinated co-oligomeric nanoparticle cores. Interestingly, transmission electron microscopy images show that magnetic nanoparticles can be encapsulated inside the crosslinked fluorinated co-oligomeric nanocomposite cores; in contrast, magnetic nanoparticles are adsorbed on the surface of fluorinated betaine-type co-oligomeric nanocomposite cores. Polymer Journal (2010) 42, 494-500; doi:10.1038/pj.2010.27; published online 21 April 2010Keywords: adsorption; encapsulation; fluorinated co-oligomeric nanoparticle; LCST; magnetite; surface modification; TEM INTRODUCTION Much attention has been devoted recently to well-dispersed magnetic colloidal particles, owing to the broad range of potential applications in the fields of ferrofluids, 1,2 high-density data storage, 3 disks and toner in printing, 4-6 magnetic resonance imaging, 7,8 enzyme immobilization, 9 rapid biological separation, 10,11 drug delivery, 12-14 biomedical materials, 15-17 immunoassays 18,19 and biosensors. 20,21 The development of colloidal-stable magnetic nanoparticles is essential from a practical point of view. The surface functionality of magnetic nanoparticles with functionalized polymers can form colloidal-stable magnetic nanoparticles. So far, numerous synthetic and natural polymers have been used to obtain stable colloidal dispersions of magnetic nanoparticles by coating and encapsulating the particles. [22][23][24][25][26][27][28][29][30][31] It is well known that fluorinated surfactants have excellent surface characteristics, including oleophobicity and hydrophobicity, neither of which can be achieved with corresponding nonfluorinated polymers. 32 Thus, it is of particular interest to develop new, tailored magnetic fluorinated polymer colloids that possess not only goo...