Geometric Frustration and Long-Range Ordering Induced by Surface Pressure Oscillation in a Langmuir–Blodgett Monolayer of Magnetic Soft Spheres

Abstract

As a step toward the bottom-up construction of magnonic systems, this paper demonstrates the use of a largeamplitude surface-pressure annealing technique to generate 2-D order in a Langmuir−Blodgett monolayer of magnetic soft spheres comprising a surfactant-encapsulated polyoxometalate. The films show a distorted square lattice interpreted as due to geometric frustration caused by 2-D confinement between soft walls, one being the air interface and the other the aqueous subphase. Hysteresis and relaxation phenomena in the 2-D layers are suggested to be due to folding and time-dependent interpenetration of surfactant chains.

The Past and the Future of Langmuir and Langmuir–Blodgett Films

“…Nontypical amphiphiles include polymers, carbonaceous compounds (carbon nanotubes and graphene), silica, other inorganic and organic−inorganic hybrid materials. Examples of inorganic and organic−inorganic materials are macrocyclic molecules, 260−265 dendrimers, 266,267 silica, 268−271 carbon-based particles, 272 black phosphorus, 273 clay nanosheets, 274 magnetic soft spheres, 275 gold nanoparticles, 276 CdS nanoparticles/quantum dots, 277,278 ionic liquids, 279−282 diureasil hybrid compounds, 283,284 and inorganic nanowires. 285 Since Sections 6 and 7 will cover considerable work on LB films of nontypical amphiphiles, in this section, we restrict ourselves to providing a general discussion of the challenges and opportunities in producing such Langmuir and LB films.…”

“…Nontypical amphiphiles include polymers, carbonaceous compounds (carbon nanotubes and graphene), silica, other inorganic and organic–inorganic hybrid materials. Examples of inorganic and organic–inorganic materials are macrocyclic molecules, − dendrimers, , silica, − carbon-based particles, black phosphorus, clay nanosheets, magnetic soft spheres, gold nanoparticles, CdS nanoparticles/quantum dots, , ionic liquids, − diureasil hybrid compounds, , and inorganic nanowires …”

Nanoscale Magnetic Arrays through Block Copolymer Templating of Polyoxometalates

“…The results presented in this work highlight POMs as promising candidates for producing patterned magnetic substrates, and the micelle templating method offers options for creating patterns of POMs at a variety of interfaces. Patterning of POMs, beyond simple deposition, has been attempted previously, − including using block copolymers. ,,,− Previous approaches, however, have incorporated POMs into the polymer in solution prior to BCP assembly at an interface. Such approaches often see effects on the BCP order and structure as a function of an increasing level of POM incorporation.…”