Bending of Layer-by-Layer Films Driven by an External Magnetic Field

Abstract

We report on optimized architectures containing layer-by-layer (LbL) films of natural rubber latex (NRL), carboxymethyl-chitosan (CMC) and magnetite (Fe3O4) nanoparticles (MNPs) deposited on flexible substrates, which could be easily bent by an external magnetic field. The mechanical response depended on the number of deposited layers and was explained semi-quantitatively with a fully atomistic model, where the LbL film was represented as superposing layers of hexagonal graphene-like atomic arrangements deposited on a stiffer substrate. The bending with no direct current or voltage being applied to a supramolecular structure containing biocompatible and antimicrobial materials represents a proof-of-principle experiment that is promising for tissue engineering applications in biomedicine.

An investigation of the synergistic effect between magnetite nanoparticles and polypyrrole in nanostructured layer‐by‐layer films

“…The precipitate was filtered, washed bountifully with clean water and dried under vacuum (30 C) for 2 days. 17,22…”

“…1 Fe 3 O 4 -np is a class of magnetic nanoparticles (NPMs) that have an inversed spinel structure formed from oxides of the formula Fe 3 O 4 by oxidative processes with the addition of Fe 2+ and Fe 3+ salts and with pH adjusted in approximately 10, under heating. 3 The Fe 2+ and Fe 3+ cations occupy the spaces between the O 2− ions, which allows two types of sites: the tetrahedral sites (the cation is in the center of the tetrahedron which has the oxygen ions as its vertices) and the octahedral (the oxygens occupying the vertices of octahedron and cations occupying the spaces between them), that is, present half of the Fe 3 + ions coordinated tetrahedrally, the other half occupying the octahedral sites with the Fe 2+ ions. 4,5 Fe 3 O 4 -np can be applied in several segments, such as microelectronic, biomedical devices for the targeted administration of drugs, for the treatment of diseases, manufacture of electrochemical sensors, among others, 2,6 as they present high-temperature rotation polarization environment and acts as electron donor.…”

“…The procedure is repeated for the assembly of a multilayered film with different supramolecular architectures on the substrate 18 . The immobilization of different materials such as NPMs, 22,23 biomolecules, 24,25 graphene‐based materials metal 19,20 among others, results in multilayered hybrid materials that present synergistic effect and achieve an optimum condition 26,27 …”

“…The procedure is repeated for the assembly of a multilayered film with different supramolecular architectures on the substrate. 18 The immobilization of different materials such as NPMs, 22,23 biomolecules, 24,25 graphene-based materials metal 19,20 among others, results in multilayered hybrid materials that present synergistic effect and achieve an optimum condition. 26,27 The present paper reports the magnetite nanoparticles associated with the Ppy for the formation of a composite by the LbL technique that presents favorable synergistic characteristics in the development of new supramolecular structures, with magnetic, electrical, and optical properties.…”

Enhanced electrical and mechanical properties of rubber/graphene film through layer-by-layer electrostatic assembly

“…Currently, few studies are focused on using layer-by-layer self-assembly technology to develop elastomer nanocomposites [42][43][44][45][46]. Generally, researches were mainly focused on the following three aspects: the modification the rubber surface to optimize its resistance to wear [42], biocompatibility with living organism [43][44][45] and tissue engineering and biomedicine [46]. For instance, Sruanganurak et al [42] deposited PMMA particles onto the natural rubber (NR) latex film by LBL technique to increase the glove's roughness and hardness.…”