Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering

Abstract

The engineering of structures across different length scales is central to the design of novel materials with controlled macroscopic properties. Herein, we introduce a unique class of self-assembling materials, which are built upon shape-and volume-persistent molecular nanoparticles and other structural motifs, such as polymers, and can be viewed as a size-amplified version of the corresponding small-molecule counterparts. Among them, "giant surfactants" with precise molecular structures have been synthesized by "clicking" compact and polar molecular nanoparticles to flexible polymer tails of various composition and architecture at specific sites. Capturing the structural features of small-molecule surfactants but possessing much larger sizes, giant surfactants bridge the gap between small-molecule surfactants and block copolymers and demonstrate a duality of both materials in terms of their self-assembly behaviors. The controlled structural variations of these giant surfactants through precision synthesis further reveal that their selfassemblies are remarkably sensitive to primary chemical structures, leading to highly diverse, thermodynamically stable nanostructures with feature sizes around 10 nm or smaller in the bulk, thin-film, and solution states, as dictated by the collective physical interactions and geometric constraints. The results suggest that this class of materials provides a versatile platform for engineering nanostructures with sub-10-nm feature sizes. These findings are not only scientifically intriguing in understanding the chemical and physical principles of the self-assembly, but also technologically relevant, such as in nanopatterning technology and microelectronics. giant molecules | shape amphiphiles | hybrid materials | microphase separation | colloidal particles P hysical properties of materials are dictated by the hierarchical arrangements of atoms, molecules, and supramolecular assemblies across different length scales. The construction and engineering of structures at each length scale, especially at the 2-to 100-nm scale (1), are critically important in achieving desired macroscopic properties. As the traditional top-down lithography techniques face serious challenges in fabricating 2D and 3D nanostructured materials with sub-20-nm feature sizes (2), the bottom-up approach based on self-organization or directed assembly of functional molecules provides a promising alternative. The past decades have witnessed the development of diverse self-assembly building blocks ranging from small-molecule surfactants (3), block copolymers (4), and dendrimers (5) to DNAs (6, 7), peptides (8), and proteins (9). Notably, these motifs have enabled the programmed self-assembly of nanomaterials as demonstrated in DNA-coated nanoparticles (10-13). These studies have greatly improved our understanding of the thermodynamics and kinetics of self-assembly processes and opened enormous possibilities in modern nanotechnology.Noncovalent interactions, such as hydrogen bonding, amphiphilic effect, π-π interacti...

Geometry induced sequence of nanoscale Frank–Kasper and quasicrystal mesophases in giant surfactants

“…The phase transition sequence of the DPOSS-1PS m giant surfactants recently has been reported to be similar to that of flexible diblock copolymers (33). With increasing length of the PS tails, the phase structure sequence follows LAM → double gyroids (DGs, space group Ia 3d) → HEX → BCC (space group Im3m) spheroidal micelles.…”

Rational design of nanomaterials from assembly and reconfigurability of polymer-tethered nanoparticles

“…For example, by increasing the length of a polystyrene tether attached to the corner of a POSS cube Cheng [22] and (d) single DNA strand [23] per building block; (e) coordination with metal ions, [24] and (f) electrohydrodynamic co-jetting methods that are used to produce multicompartmentalized building blocks [19,25,26] . Panel (c) reprinted by permission from Macmillan Publishers Ltd.: Nature Nanotechnology [22] , Polymers/Soft Matter Prospective Article et al [31] can tune between lamella, the double-gyroid, hexagonal tubes, and BCC micelles, as seen in Fig. 2(b).…”

“…[21,27] This technique has recently been used to interchange nearly every portion of the building block. [21,[30][31][32] Examples include the ability to interchange head groups from polyhedral oligomeric silsesquioxane (POSS) cages to gold NPs, as well as to exchange polymer types such as polystyrene or poly(methyl methacrylate) (PMMA); additionally, the size, number, and placement of these chemically distinct domains can be controlled, such as tethering a single corner of a POSS molecule with one or more polymer tethers. [21,27,[30][31][32] Related methods have been used to create additional types of polymer-NP composite blocks.…”

“…[11] Recently, many of these initial findings have also been corroborated with experiments. [31] Given the close relationship between tethered NPs and liquid crystals, [58] the roles of the shape of the NP head group have also been extensively investigated. [12,13,[67][68][69][70] In these cases, it was again found that structures and transitions similar to those in liquid crystals were observed, such as lamella, gyroids, cylinders, and micelles.…”

From dendrimers to fractal polymers and beyond

“…This generates a tailored molecular assembly possessing enhanced physical and/or structural characteristics for a utilitarian outcome. For example, high molecular weight species can easily be made soluble in aqueous or non-aqueous media, based on the incorporated functionality (Yu et al, 2013). As well, and perhaps most importantly, with the advent of dendritic synthetic strategies, chemists now have better insight to incorporate precise control over the placement of all the components of macromolecular materials that could be fully and unequivocally characterized.…”