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

Abstract

The development of magnetic hybrid films containing diblock copolymers (DBCs) and magnetic nanoparticles (NPs) by printing is a highly promising method for scalable and low-cost fabrication. During printing, the drying and arrangement kinetics of the DBC and magnetic NPs play an important role in the film formation concerning morphology and magnetic properties. In this study, the morphology evolution of ultrahigh molecular weight DBC polystyrene-block-poly(methyl methacrylate) and magnetic iron platinum (FePt) NPs is investigated with grazing-incidence small-angle X-ray scattering (GISAXS) in situ during printing. For comparison, a pure DBC film is printed without FePt NPs under the same conditions. The GISAXS data suggest that the addition of NPs accelerates the solvent evaporation, leading to a faster film formation of the hybrid film compared to the pure film. As the solvent is almost evaporated, a metastable state is observed in both films. Compared with the pure film, such a metastable state continues longer during the printing process of the hybrid film because of the presence of FePt NPs, which inhibits the reorganization of the DBC chains. Moreover, investigations of the field-dependent magnetization and temperature-dependent susceptibility indicate that the printed hybrid film is superparamagnetic, which makes this film class promising for magnetic sensors.

Site-Selective Assembly of Centimeter-Scale Arrays of Precisely Oriented Magnetic Nanoellipsoids

“…The M r along the ellipsoids’ long axis decreased from 3.3 × 10 –6 to 0.6 × 10 –6 emu, whereas the M r along their short axis slightly fluctuated (Figure D and Figure S12). This phenomenon can be attributed to the increase in the disorderness of the magnetic moments due to increased thermal fluctuation of atoms of the ellipsoids at elevated temperature …”

“…This phenomenon can be attributed to the increase in the disorderness of the magnetic moments due to increased thermal fluctuation of atoms of the ellipsoids at elevated temperature. 40…”

Self-Assembly of Polymer-Modified FePt Magnetic Nanoparticles and Block Copolymers

“…N , N , N ′, N ″, N ″-pentamethyldiethylenetriamine (PMDETA) and anisole were degassed and stored under argon in a glovebox. Pt(acac) 2 and Fe(CO) 5 in octadecene were used to prepare the FePt NPs, as previously published by L i et al [ 31 ] and C ao et al [ 13 ]. Further details on the coating can be found in the Supporting Materials .…”

“…The addition of NPs also introduces additional surface area from the particles and eventually adds stabilizing molecules or ions [ 7 ]. In general, different methods of film preparation, like spin coating [ 5 , 10 ], dip coating [ 4 ], nanopatterning [ 11 ], evaporation-induced self-assembly (EISA) [ 12 ], printing [ 13 ], solution casting [ 9 ], and photochemical etching [ 14 ], have been applied.…”

Relationship between deposition techniques and nanoparticle dispersions for flexible and printed electronics

“…This relationship between the minimum wet film thickness and the capillary number means that thicker films will require an increase in slot-die head speed and flow-rate. Prior studies have investigated the film formation process and morphology development during slot-die coating of di-block copolymer solutions [116][117][118][119]. However, no studies have examined the deposition of PS-b-P2VP micellar arrays using slot-die coating.…”