Functionalized Nanostructures with Liquid-Like Behavior: Expanding the Gallery of Available Nanostructures

Abstract

Recently, we have developed a novel family of functionalized nanostructures that exhibit liquid‐like behavior in the absence of solvents and preserve their nanostructure in the liquid state. The gallery of nanostructures developed so far includes functionalized silica and magnetic iron oxide nanoparticles, layer‐like organosilicate nanoparticles, polyoxometalate clusters, and organic–inorganic hybrid networks. In an effort to demonstrate the wider applicability of this concept and to provide a deeper insight into this class of materials, the present work cites additional paradigms of functionalized nanostructures with similar behavior as above. In one case, surface functionalization of anatase nanoparticles (TiO2, an inorganic nanostructure) with a quaternary ammonium organosilane leads to ionically modified nanoparticles that, when electrostatically combined with a poly(ethylene glycol) (PEG)‐tailed sulfonate anion, exhibit liquid‐like behavior in the absence of solvents. In a different but quite interesting case of a bionanostructure, ion‐exchange functionalization of a DNA oligonucleotide with a PEG‐tailed quaternary ammonium cation leads to an easily separable liquid derivative with attractive features. These examples show the versatility of this concept over a range of nanostructures.

Hairy nanoparticle assemblies as one-component functional polymer nanocomposites: opportunities and challenges

“…[75] Increased fluidity is found in a particular class of HNPsknown as Nanoparticle Ionic Materials (NIMs) where the bonding of the corona to the core is ionic in nature. [76,77,[80][81][82] MD simulations suggest that even though the ionic bonds between the corona and the particle are stronger than thermal energy, the hairs are able to hop from particle to particle, offering an additional relaxation mode. [83] This hopping effect dominates the intermediate scale dynamics (10 s of nanoseconds), while NMR studies show that the fast dynamics (nanoseconds) of the hairs are essentially unchanged.…”

Diffusivities, viscosities, and conductivities of solvent-free ionically grafted nanoparticles

“…28. The effects of temperature on the dynamics have been thoroughly examined, 1,10,11,[17][18][19][21][22][23]27 but only few experimental studies prepared a series of samples with modied oligomer lengths 25 or graing densities.…”

Dynamics of solvent-free grafted nanoparticles

“…Experimental realization of such solvent-free composite systems has been recently demonstrated in the form of "nanoparticle organic hybrid materials" (NOHMs). [10][11][12][13][14][15] These are core-shell systems consisting of a hard (inorganic) core and a soft (organic) oligomer corona. By varying the molecular weight and grafting density of the arms (corona), and the core particle size, they can display properties that span from glasses, stiff waxes, and gels (at high volume fractions), to simple liquids comprised of molecular building blocks (at a) Author to whom correspondence should be addressed.…”