Influence of Dendrimer Additives on the Dewetting of Thin Polystyrene Films

Abstract

A small mass concentration of poly(benzyl ether) dendrimer added to a low molecular mass polystyrene is found to inhibit the dewetting of a thin (≈50 nm) polystyrene film from an acid-etched silicon substrate. The inhibition effect is found to depend on generation number where the lowest generation (G ) 3) tested was the most effective. Our findings are qualitatively similar to previous observations by Barnes et al. [Macromolecules 2000, 33, 4177-4185.] where the addition of fullerenes ("buckyballs", C60) similarly inhibited the dewetting of thin polystyrene and polybutadiene films. Thus, dewetting inhibition by nanoparticles appears to be a general effect, although certain conditions apparently need to be met for its occurrence. Specifically, a general tendency for the particles to segregate to the solid substrate seems to be required and the interaction between the particles and polymer must not be too unfavorable. The phase boundaries of the dendrimer-polymer mixtures depend on the generation, the higher generation being more miscible in terms of mass fraction. This suggests that the driving force for the dendrimer to segregate to the boundary is varied by changing the generation number, thus giving rise to a dendrimer generational effect on dewetting suppression.

Correlated Roughness in Polymer Films Containing Maghemite Nanoparticles

“…Thus, not enough material is present to form a uniform film and to prevent the onset of dewetting. Although nanoparticles are well-known to prevent dewetting, [38][39][40][41][42][43][44][45][46] in the ultrathin film case nanoparticles retard dewetting. 9 Recently, a similar kind of structure was reported in the case of an ultrathin film using similar materials.…”

“…17, 18 Krishnan and Mackay et al reported the similar effects using dendrimer and PS nanoparticles. 19,20 McGarrity et al reported recently that the inhibition of dewetting due to added nanoparticles to the supported thin polymer films occurs because of migration of nanoparticles to the substrate. 21 Therefore, the film thickness of a nanocomposite, either partially dewetted or wetted film, which is produced by spin-coating, is statistically an average value.…”

Facile Method of Controlling Monomer Sequence Distributions in Random Copolymers

“…These include the development of efficient and inexpensive adhesion promoters with tailored characteristics, [5,6,7] generation of polymeric particles with tailorable sizes and rheological characteristics; [18] which could then be used as solution viscosity regulators or as thin film stabilizers. [19,20] A variant of the method described below can also be utilized in fabricating selective adsorption probes that can be used, for instance, as a stationary chromatography phase in interaction chromatography for chemical identification of macromolecular targets. Our synthetic scheme is based on computer simulations of Khokhlov and co-workers, who have shown that random copolymers with tunable monomer sequence distributions can be prepared by selectively "coloring" certain monomers of a parent A homopolymer with another species, say B.…”

Enhancing the stability of polystyrene ultrathin films by using star-shape polymers as dewetting inhibitors

“…In recent years, many researchers have investigated the mechanism of this phenomenon and have discovered that other nanoparticles can also be used as dewetting inhibitors. [23][24][25][26][27][28][29][30][31][32][33] The suppression of thin film dewetting can also be achieved by reducing the mobility of polymeric chains. This technique is based on kinetic strategy.…”