Nanoparticle Self-Assembly: From Design Principles to Complex Matter to Functional Materials

Abstract

The creation of matter with varying degrees of complexities and desired functions is one of the ultimate targets of self-assembly. The ability to regulate the complex interactions between the individual components is essential in achieving this target. In this direction, the initial success of controlling the pathways and final thermodynamic states of a self-assembly process is promising. Despite the progress made in the field, there has been a growing interest in pushing the limits of self-assembly processes. The main inception of this interest is that the intended self-assembled state, with varying complexities, may not be “at equilibrium (or at global minimum)”, rendering free energy minimization unsuitable to form the desired product. Thus, we believe that a thorough understanding of the design principles as well as the ability to predict the outcome of a self-assembly process is essential to form a collection of the next generation of complex matter. The present review highlights the potent role of finely tuned interparticle interactions in nanomaterials to achieve the preferred self-assembled structures with the desired properties. We believe that bringing the design and prediction to nanoparticle self-assembly processes will have a similar effect as retrosynthesis had on the logic of chemical synthesis. Along with the guiding principles, the review gives a summary of the different types of products created from nanoparticle assemblies and the functional properties emerging from them. Finally, we highlight the reasonable expectations from the field and the challenges lying ahead in the creation of complex and evolvable matter.

When Design Meets Function: The Prodigious Role of Surface Ligands in Regulating Nanoparticle Chemistry

“…4,45,46 In this context, the process of self-assembly is arguably the most efficient way to organize particles into well-ordered structures. 5,47,48 After showcasing great prospects in the initial years, the area of self-assembly is now transforming from a static (equilibrium) to a dynamic (nonequilibrium) regime. 49−54 This is because of the realization that the function and complexity of a self-assembled structure depend on the position they occupy in the free energy landscape.…”

“…49−54 This is because of the realization that the function and complexity of a self-assembled structure depend on the position they occupy in the free energy landscape. 47,53 The process of equilibrium self-assembly is followed when the main target is to create static structures with high reproducibility and yield, such as the formation of crystals, proteins, lipid bilayers, etc. 47,48 On the other hand, nonequilibrium self-assembly is followed when the target is to create dissipative and nondissipative states (metastable and kinetically trapped states occupying a local thermodynamic minimum).…”

“…47,53 The process of equilibrium self-assembly is followed when the main target is to create static structures with high reproducibility and yield, such as the formation of crystals, proteins, lipid bilayers, etc. 47,48 On the other hand, nonequilibrium self-assembly is followed when the target is to create dissipative and nondissipative states (metastable and kinetically trapped states occupying a local thermodynamic minimum). 47,53,55,56 A biological cell and blood clotting phenomena in a damaged tissue are the classical examples of the above two classes of selfassembled structures, respectively.…”

“…47,48 On the other hand, nonequilibrium self-assembly is followed when the target is to create dissipative and nondissipative states (metastable and kinetically trapped states occupying a local thermodynamic minimum). 47,53,55,56 A biological cell and blood clotting phenomena in a damaged tissue are the classical examples of the above two classes of selfassembled structures, respectively. 47,52,57 A detailed classification of all these different self-assembled states is beyond the scope of this perspective, and many prominent reviews are available that give a fair understanding of the equilibrium and the nonequilibrium self-assembly processes.…”

Reversible assembly of nanoparticles: theory, strategies and computational simulations

“…Many strategies have been reported to control the assembly of NPs through the manipulation of intermolecular interactions which occur between the designed molecules (or ligands) used to functionalize their surface or by the interaction of the external field and the NP core. [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] In addition, the considerable progress and knowledge gained in recent decades on nanoparticle assembly have enabled the implementation of an increasing number of strategies for reversible nanoparticle assembly, i.e., processes in which both assembly and disassembly are controlled. In addition to being of interest for fundamental studies, these developments further broaden the range of applications and the possibility of developing innovative devices using nanoparticles.…”