Effectivity of plasma etching on template removal of reverse micelle deposited nanoparticles

Relationship between deposition techniques and nanoparticle dispersions for flexible and printed electronics

“…The role of the salt is particularly important, and can lead to differing effects. For example, Turak et al [93][94][95] showed that poor ordering and agglomeration are observed when the molar ratio of FeCl 3 to the P2VP polymer (known as the loading ratio [44,96]) is above a critical threshold value, whereas Spatz, et al [82] observed that below a critical loading ratio, PS-b-P2VP micelles loaded with chloroauric acid, a precursor for gold, resulted in agglomerated islands of loaded micelles. They attributed this latter behaviour to repulsive electrostatic interactions which result from charged micelles, whereas in the first case, the strong interaction of iron and the vinyl pyridine resulted in an unraveling of the micelles [35,97].…”

“…One potential route for producing well-ordered arrays with significantly larger interparticle distance is to increase the size of the micelles. However, due to the relationship between the core size and the resultant nanoparticle formed after plasma etching (see SI figure S1) [44], this is not a trivial change to the nanoparticle recipe. As the PS forms the corona of the micelle, increasing the molecular weight of the PS copolymer [53] has been seen as a potential route to increase the size of the micelles without increasing the size of the resulting nanoparticles.…”

“…Using one or multiple precursors, combined with plasma etching, a wide variety of material systems can be produced taking advantage of aqueous chemistry. Typically, plasma etching of the two-dimensional arrays of loaded reverse micelles can be used to remove the polymer shell and expose the target nanoparticle [44] while maintaining the interparticle spacing and two dimensional order of the micellar templates (see SI figure S1 for an array of loaded reverse micelles and the resultant lanthanum oxide nanoparticles after plasma etching). Polystyrene-bpoly(2-vinylpyridine)(PS-b-P2VP) has proven to be a particularly useful and versatile template, due to its low critical micelle concentration [45,46], ability to complexate with many precursors [47,48], high stability with salt incorporation [35,47,49] and highly tunable self-assembly properties [50].…”