Self‐Assembled Biomimetic Capsules for Self‐Preservation

The inorganic semiconductor is an attractive material in sewage disposal and solar power generation. The main challenges associated with environment‐sensitive semiconductors are structural degradation and deactivation caused by the unfavorable environment. Here, inspired by the pomegranate, a self‐protection strategy based on the self‐assembly of silver chloride (AgCl) particles is reported. The distributed photosensitive AgCl particles can be encapsulated by themselves through mixing aqueous silver nitrate and protic ionic liquids (PILs). A probable assembling mechanism is proposed based on the electrostatic potential investigation of PILs cations. The AgCl particles inside the shell maintain their morphology and structure well after 6 months light‐treatment. Moreover, they exhibit excellent photocatalytic activity, same as newly prepared AgCl particles, for degradation of methyl orange (MO), neutral red (NR), bromocresol green (BG), rhodamine B (RhB), Congo red (CR), and crystal violet (CV).     

Fluorescent Nanoparticles Based on Self‐Assembled π‐Conjugated Systems

π‐Conjugated molecules are interesting components to prepare fluorescent nanoparticles. From the use of polymer chains that form small aggregates in water to the self‐assembly of small chromophoric segments into highly ordered structures, the preparation of these materials allows to develop systems with applications as sensors or biolabels. The potential functionalization of the nanoparticles can lead to specific probing. This progress report describes the recent advances in the preparation of such emittive organic nanoparticles.     

Multifunctional Nanoparticles Self‐Assembled from Small Organic Building Blocks for Biomedicine

Supramolecular self‐assembly shows significant potential to construct responsive materials. By tailoring the structural parameters of organic building blocks, nanosystems can be fabricated, whose performance in catalysis, energy storage and conversion, and biomedicine has been explored. Since small organic building blocks are structurally simple, easily modified, and reproducible, they are frequently employed in supramolecular self‐assembly and materials science. The dynamic and adaptive nature of self‐assembled nanoarchitectures affords an enhanced sensitivity to the changes in environmental conditions, favoring their applications in controllable drug release and bioimaging. Here, recent significant research advancements of small‐organic‐molecule self‐assembled nanoarchitectures toward biomedical applications are highlighted. Functionalized assemblies, mainly including vesicles, nanoparticles, and micelles are categorized according to their topological morphologies and functions. These nanoarchitectures with different topologies possess distinguishing advantages in biological applications, well incarnating the structure–property relationship. By presenting some important discoveries, three domains of these nanoarchitectures in biomedical research are covered, including biosensors, bioimaging, and controlled release/therapy. The strategies regarding how to design and characterize organic assemblies to exhibit biomedical applications are also discussed. Up‐to‐date research developments in the field are provided and research challenges to be overcome in future studies are revealed.     

Dual pH‐Induced Reversible Self‐Assembly of Gold Nanoparticles by Surface Functionalization with Zwitterionic Ligands

The dual pH‐induced reversible self‐assembly (PIRSA) of Au‐nanoparticles (Au NPs) is reported, based on their decoration with the self‐complementary guanidiniocarbonyl pyrrole carboxylate zwitterion (GCPZ). The assembly of such functionalized Au NPs is found at neutral pH, based on supramolecular pairing of the GCPZ groups. The resulting self‐assembled system can be switched back to the disassembled state by addition of base or acid. Two predominant effects that contribute to the dual‐PIRSA of Au NPs are identified, namely the ionic hydrogen bonding between the GCPZ groups, but also a strong hydrophobic effect. The contribution of each interaction is depending on the concentration of GCPZ on NPs, which allows to control the self‐assembly state over a wide range of different water/solvent ratios.     

Self‐Assembled Networked PbS Distribution Quantum Dots for Resistive Switching and Artificial Synapse Performance Boost of Memristors

With the advent of the era of big data, resistive random access memory (RRAM) has become one of the most promising nanoscale memristor devices (MDs) for storing huge amounts of information. However, the switching voltage of the RRAM MDs shows a very broad distribution due to the random formation of the conductive filaments. Here, self‐assembled lead sulfide (PbS) quantum dots (QDs) are used to improve the uniformity of switching parameters of RRAM, which is very simple comparing with other methods. The resistive switching (RS) properties of the MD with the self‐assembled PbS QDs exhibit better performance than those of MDs with pure‐Ga₂O₃ and randomly distributed PbS QDs, such as a reduced threshold voltage, uniformly distributed SET and RESET voltages, robust retention, fast response time, and low power consumption. This enhanced performance may be attributed to the ordered arrangement of the PbS QDs in the self‐assembled PbS QDs which can efficiently guide the growth direction for the conducting filaments. Moreover, biosynaptic functions and plasticity, are implemented successfully in the MD with the self‐assembled PbS QDs. This work offers a new method of improving memristor performance, which can significantly expand existing applications and facilitate the development of artificial neural systems.     

Thermoreversible Self‐Assembly of Perfluorinated Core‐Coronas Cellulose‐Nanoparticles in Dry State

Self‐assembly of nanoparticles (NPs) forming unique structures has been investigated extensively over the past few years. However, many self‐assembled structures by NPs are irreversible, because they are generally constructed using their suspensions. It is still challenging for NPs to reversibly self‐assemble in dry state, let alone of polymeric NPs with general sizes of hundreds of nm. Herein, this study reports a new reversible self‐assembly phenomenon of NPs in dry state, forming thermoreversible strip‐like supermolecular structures. These novel NPs of around 150 nm are perfluorinated surface‐undecenoated cellulose nanoparticles (FSU‐CNPs) with a core‐coronas structure. The thermoreversible self‐assembled structure is formed after drying in the air at the interface between FSU‐CNP films and Teflon substrates. Remarkably, the formation and dissociation of this assembled structure are accompanied by a reversible conversion of the surface hydrophobicity, film transparency, and anisotropic properties. These findings show novel feasibility of reversible self‐assembly of NPs in dry state, and thereby expand our knowledge of self‐assembly phenomenon.     

Strain‐Driven Self‐Assembled Network of Antidots in Complex Oxide Thin Films

Structural strain due to lattice mismatch is used to promote the formation of a self‐assembled network of antidots in highly epitaxial La_2/3Sr_1/3MnO₃ thin films grown on (001) oriented SrTiO₃ substrates by radiofrequency magnetron sputtering. Size, depth, and separation between antidots can be controlled by changing deposition parameters and the miscut angle of the substrate. This morphology exhibits a remarkable magnetic anisotropy and offers unique opportunities for versatile nanostencils for the preparation of nano‐object networks that can be of major relevance for the fabrication of oxide‐based magnetic and magnetoelectronic devices.