Out of Equilibrium Self-Assembly of Janus Nanoparticles: Steering It from Disordered Amorphous to 2D Patterned Aggregates

Abstract

Solvent evaporation driven self-assembly of Janus nanoparticles (J-NPs) has been simulated employing lattice-gas models to investigate the possible emergence of new superlattices. Depending on the chemical nature of NP faces (hence solvophilicity and relative interaction strength), zebra-like or check-like patterns and micellar agglomerates can be obtained. Vesicle-like aggregates can be produced by micelle-based corrals during heterogeneous evaporation. Patterns formed during aggregation appear to be robust against changes in evaporation modality (i.e., spinodal or heterogeneous) or interaction strengths, and they are due to a strictly nanoscopic orientation of single J-NPs in all cases. Due to the latter feature, the aggregate size growth law N(t) ∝ t has its exponent a markedly depending on the chemical nature of the J-NPs involved in spite of the unvaried growth mechanism. We interpret such a finding as connected to the increasingly stricter orientation pre-requirements for successful (binding) NP landing upon going from isotropic (a ≃ 0.50), to "zebra" (a ≃ 0.38), to "check" (a ≃ 0.23), and finally to "micelle" (a = 0.15-0.17) pattern forming NPs.

Dynamic Interfacial Trapping of Janus Nanorod Aggregates

“…Manipulating how individual nanoparticles and their aggregates self-assemble is crucial for realizing new classes of optoelectronic devices; − improving the efficiency of photovoltaic devices; − wielding novel medical imaging probes; − and exploring innovative polymeric nanocomposites that are optically active. − More specifically, using external fields − to guide the assembly of nanoparticles is an effective way to enable practical scaling-up of these new technologies and obtain vectorial properties for a given application . This is relevant at an interfacial level for multiphase nanomaterials possessing interfaces with complex structures as they dictate the equilibrium and nonequilibrium rheological properties of these materials. − For instance, in the case of amphiphilic rigid Janus nanoparticle surfactants at fluid–fluid interfaces, both shape and chemical anisotropy within the same particle offer a way to control particle orientation and self-assembly at the interfacial level. − …”

Bodipy-Loaded Micelles Based on Polylactide as Surface Coating for Photodynamic Control of Staphylococcus aureus

“…The idea of using micelles of mPEG-(PLA)n copolymers as surface releasing coatings is based on two consideration: the first one is about the degradability of copolymers, due to the presence of the polylactide blocks, that leads to a temporary coating; the second one is the presence of the mPEG block that preserves the surface from adsorption of proteins and adhesion of cells after its decontamination and until the following process of surface disinfection. The linear and branched structures were synthesized, since we already noted that the copolymer structure can strongly influence chemical-physical properties as well as the biological behavior of supramolecular aggregates, such as micelles or vesicles or both when the copolymer is neutral and charged [19][20][21][33][34][35][36][37][38][39][40][41][42][43]. Table 1.…”

Self-Assembly of Amphiphilic Janus Particles Confined between Two Solid Surfaces

“…Although much activity so far has focused on two-faced JPs, theoretical studies have also concerned multiblock colloidal spherical particles and particles of different shapes. , Self-assembly of JPs in various environments has been studied, including different solvents, mixtures with isotropic particles, − interfaces, and magnetic or electric fields …”