Spray‐Coating Magnetic Thin Hybrid Films of PS‐b‐PNIPAM and Magnetite Nanoparticles

Abstract

Spray coating is employed to fabricate magnetic thin films composed of the diblock copolymer polystyrene‐block‐poly(N‐isopropylacrylamide) and Fe3O4 magnetic nanoparticles (MNPs) functionalized with hydrophobic coatings. The kinetics of structure formation of the hybrid films is followed in situ with grazing incidence small angle X‐ray scattering during the spray deposition. To gain a better understanding of the influence of MNPs on the overall structure formation, the pure polymer film is also deposited as a reference via an identical spray protocol. At the initial spraying stage, the hybrid film (containing 2 wt% of MNPs) exhibits a faster formation process of a complete film as compared to the reference. The existence of MNPs depresses the dewetting behavior of polymer films on the substrate at macroscale and simultaneously alters the polymer microphase separation structure orientation from parallel to vertical. As spraying proceeds, MNPs aggregate into agglomerates with increasing sizes. After the spray deposition is finished, both samples gradually reach an equilibrium state and magnetic films with stable structures are achieved in the end. Superconducting quantum interference device investigation reveals the superparamagnetic property of the sprayed hybrid film. Consequently, potential application of sprayed films in fields such as magnetic sensors or data storage appears highly promising.

Tailoring Ordered Mesoporous Titania Films via Introducing Germanium Nanocrystals for Enhanced Electron Transfer Photoanodes for Photovoltaic Applications

“…[ 29 ] In our study, due to the surface functionalization, the germanium nanocrystals (GeNCs) maintain their solubility in solvents and have a preferential selectivity to a specified block of a DBC. [ 30,31 ] In addition, due to effects like steric hindrance, the possibility of forming big GeNC agglomerates can be mitigated by the DBC matrix. [ 31 ] These factors contribute to the exquisite tailoring of the mesoporous TiO 2 nanostructures by introducing GeNCs in combination with the metal oxide precursor.…”

“…[30,31] In addition, due to effects like steric hindrance, the possibility of forming big GeNC agglomerates can be mitigated by the DBC matrix. [31] These factors contribute to the exquisite tailoring of the mesoporous TiO 2 nanostructures by introducing GeNCs in combination with the metal oxide precursor.…”

In Situ Study of FePt Nanoparticles‐Induced Morphology Development during Printing of Magnetic Hybrid Diblock Copolymer Films

“…[7,15] In our previous studies, the kinetics of magnetic hybrid films during spray coating were successfully investigated. [17,26] However, spray coating is a layer-by-layer deposition technology, which is different from printing.…”

“…The obtained magnetic data show that the printed magnetic hybrid NP‐DBC film is superparamagnetic, which is beneficial to scale up the flexible magnetic film fabrication for magnetic sensors. [ 16,26 ] Moreover, the present work provides a profound insight for the future optimization of printed magnetic hybrid NP‐DBC films, as well as other hybrid NP‐DBC systems (such as zirconium oxide NP‐DBC and gold NP‐DBC). [ 10,11 ]…”

Synthesis of Riboflavin‐Based Macromolecules through Low ppm ATRP in Aqueous Media

“…We report synthesis of riboflavin‐based macromolecules composed of poly( N ‐isopropylacrylamide) (PNIPAM), poly(oligo(ethylene glycol) acrylate (POEGA), and poly(2‐hydroxyethyl acrylate) (PHEA). PNIPAM is one of classical thermo‐responsive polymers due to its coil‐to‐globule transition above 32 °C in aqueous media (LCST), close to human body temperature . These interesting properties make PNIPAM a candidate for biomedical applications including gene delivery and delivery of therapeutic molecules .…”