Janus Magnetic Nanoparticles with a Bicompartmental Polymer Brush Prepared Using Electrostatic Adsorption to Facilitate Toposelective Surface-Initiated ATRP

Abstract

Utilizing the inherent negative charge of mica surfaces, amine-functionalized magnetic nanoparticles (Fe3O4/NH2) were electrostatically adsorbed onto the mica such that surface-initiated ATRP could be used to grow poly(n-isopropylacrylamide) (PNIPAM) from the exposed hemisphere. By reducing the solution pH, a positive charge generated on the mica was used to release the nanoparticles from the substrate. A second ATRP reaction was carried out to grow poly(methacrylic acid) (PMAA) from the initiated surfaces. As a result, the Fe3O4/NH2 core has a polymer shell with one hemisphere PMAA and the other hemisphere PNIPAM-b-PMAA resulting in the PMAA-Fe3O4-PNIPAM-b-PMAA bicompartmental polymer Janus nanoparticles. Elemental and functional group compositions were confirmed using ATR-FTIR, XPS, and EDS. Imaging with AFM, SEM, and TEM showed the evolution of the Janus nanoparticle morphology. This study demonstrates a facile and innovative scheme involving a noncovalent solid protection technique combined with sequential, surface-confined controlled radical polymerizations for the production of multicomponent nanocomposites.

Fetuin-A adsorption and stabilization of calcium carbonate nanoparticles in a simulated body fluid

“…42,43 After Fetuin-A adsorption, these Ca peaks were no longer observed (Fig. 2D), confirming the presence of the carbonate ((C-O) 3 ) group. High resolution carbon and oxygen scans were also performed ( Fig.…”

“…2D-G), and adsorption-related C and O transitions observed. 46,47 Lastly, results for the O 1s high-resolution XPS analysis on the CaCO 3 nanoparticles revealed a 528 eV binding energy attributable to the oxygen ((C-O) 3 ) in CaCO 3 . 44 An additional peak was observed at approximately 290 eV in the CaCO 3 sample (Fig.…”

“…[1][2][3][4] For example, biocompositesinorganic materials combined with proteins, natural polymers, or other biomolecules-display greater biocompatibility than solely inorganic, synthetic materials. [1][2][3][4] For example, biocompositesinorganic materials combined with proteins, natural polymers, or other biomolecules-display greater biocompatibility than solely inorganic, synthetic materials.…”

“…TEM images of CaCO3 showing aggregation (A and B). At high resolution, a rhombohedral-like structure is observed which is characteristic of calcite materials (C).…”

Fabrication of Ternary Hybrid Colloids via In‐Situ Polymerization at the Interface of Oil/Water Emulsion

“…[17,18] Progress in nanotechnology has made it possible to construct numerous asymmetric colloids with different functionalities. The methods to fabricate the asymmetric colloids are generally divided into four categories, interface protection, [19][20][21][22] phase separation, [23][24][25] self-assembly, [26][27][28] and surface nucleation and growth. [29][30][31][32] Among those methods, surface generated surrounding SLCs, and the residual VBC and DVB in oil phase were gradually migrated to the oil/water interface of the emulsion for further polymerization, and thus THCs were fabricated.…”