Surface Topography and Composition of Deuterated Polystyrene−Poly(bromostyrene) Blends

Abstract

Surface structure, obtained from atomic force microscopy and X-ray reflectivity, and surface chemical analysis data, obtained from X-ray photoelectron and static secondary ion mass spectroscopy, are reported for blends of poly(p-bromostyrene) with poly(deuteriostyrene). When high speeds are used in the spin-coating process, the atomic force microscopy measurements reveal that the surface structure consists of islands, the distribution and number changing with the poly(bromostyrene) content. A ribbon structure is observed at just above 50% (w/w) poly(bromostyrene) in the mixture. These ribbons merge to form more continuous structures, leaving voids at higher concentrations. X-ray reflectivity data from the films were consistent with the topographical features observed with the AFM. At low spinning speeds, continuous films with little or no topographical structure are formed. The islands observed at high spinning speeds are predominately poly(bromostyrene) and reflect the importance of thermodynamic and kinetic driving forces in their formation.

Surface-directed phase separation in nanometer polymer films: self-stratification and pattern replication

“…5a). Such solvent quench [39,[54][55][56][57][58][59][60] accompanies the spin-casting process ( Fig. 5b-f) [38].…”

“…Laterally separated phase domains present in solvent-quenched thin films (and corresponding to column-like morphologies in temperature-quenched samples with flat surfaces) are always accompanied by free surface undulations [39,[54][55][56][57][58][59][60][61][62]. Different theories, referring to various solvent effects, try to account for this phenomenon [59,[61][62].…”

Development of a nanoporous and multilayer drug-delivery platform for medical implants

“…Similar holes or pores have been reported with a polymer blend phase separating via a spinodal decomposition mechanism. 25 At the initial stages of spin coating, the upper part of the substrate film was dissolved, forming a blend solution since chloroform is a common solvent for the selected polymers. This hypothesis was verified by the SE data showing that the thickness of the substrate film was reduced after the deposition of the subsequent film (as depicted in Figure 3C and D).…”

“…By varying the size (ie, diameter, volume) and number of the porous reservoirs, a range of therapeutic agent loading levels can be achieved. 25 In the case of DES where the drug targets different sites of the vessel, it is necessary to control the porosity of the stent nanocoatings for directional and tailored drug loading and resultant release. In this study we found that by tuning the spin-coating parameters, the pore distribution and dimensions, interconnectivity, and density of the materials can be controlled.…”

“…The polymeric films were cleaned by N 2 flow and incubated in PRP at room temperature. AFM was then applied for platelet visualization onto the drug-free triple layers (PLGA 25]-PCL) at 1-and 2-hour intervals in the tapping mode for better image acquisition and avoidance of platelet damage. 14 The quantities that were used for the evaluation of surface roughness of the multilayer films before and during platelet adhesion were peak-to-valley (R y ) distance and root-mean-square roughness (R q ).…”