Unusual dynamical arrest in polymer grafted nanoparticles

Abstract

We present results of temperature dependent measurements of dynamics of polymer grafted nanoparticles with high grafting density with star polymerlike morphology. We observed for the low grafting density and hence low functionality sample, a dynamically arrested state with lowering of temperature, similar to what was conjectured earlier. However the high grafting density sample shows liquidlike relaxation at all measured temperatures. Possible origin of dynamical arrest in the two grafting density sample is discussed.

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

“…For example, the same kinetically trapped soft glasses seen in star polymers [26,70,71] can also be seen in concentrated HNP systems. [72] The relaxation modes and spectrum of a polymer chain depend on both intra-chain connectivity and the local packing of near neighbor chain segments.…”

Surface and Interface Analyses of Polymer Brushes by Synchrotron Radiation

“…As a different approach to the dynamics of polymer brushes, the study of dynamical behavior of polymer grafted nanoparticles is significant. However the studies of dynamical behavior of polymer grafted nanoparticles are very few, 66,67) and the details such dynamical behavior is still unknown.…”

Communication: Unusual dynamics of hybrid nanoparticles and their binary mixtures

“…However, no effort has been made in understanding their dynamics, especially for concentrated solutions or melts where these hybrid nanostructures are expected to form gel, glass, or crystalline phases similar to that observed for block copolymer 5 or star polymers. 6,16 Recently, we have shown 11 how temperature and wave vector dependent dynamics in such hybrid nanoparticles can show counterintuitive behavior as compared to the related star polymer melts. 8 Here, we significantly extend that work to present the results on the dynamics of such particles with different functionality f as well as their binary mixtures.…”

“…[1][2][3][4][5][6][7] Block copolymer micelles, 5 star polymers, [6][7][8] and microgel particles 3,4 constitute few examples of such materials, which have been extensively studied. However, hybrid nanoparticles [9][10][11] having an inorganic core and organic or polymeric shell, which also belong to the same class of materials, have not received as much attention. This is slightly surprising since these hybrid particles have gained tremendous importance due to their ability to form self-assembled ordered structures with very interesting optical, electrical, or thermomechanical properties.…”

“…The results presented here are based on hybrid particles with core of gold nanoparticles and corona of thiol terminated polystyrene ͑PST͒ synthesized by a method described earlier. 11,17 Both the core size as well as the grafting density of PST chains on the gold surface were varied to obtain hybrid particles with various sizes. Binary mixtures of two such hybrid particles, having different sizes, were prepared by mixing them in tetrahydrofuran solutions in various fractions and subsequent evaporation of the solvent, followed by drying in vacuum.…”