XPS Studies of Fluorinated Acrylate Polymers and Block Copolymers with Polystyrene

Abstract

X-ray photoelectron spectroscopy (XPS) has been used to investigate the surface characteristics of various novel fluorinated acrylate homopolymers [1,1-dihydroperfluorooctyl acrylate (PFOA), 1,1-dihydroperfluorooctyl methacrylate (PFOMA), 1,1,2,2-tetrahydroperfluorooctyl acrylate (PTAN)] as well as diblock copolymers consisting of both a fluorocarbon block of PFOA and a hydrocarbon block of polystyrene (PS). This technique allows nondestructive depth profiling of the top ∼100 Å of a material, providing both elemental composition and chemical state information. Due to the low surface energy of the fluorinated species, its enhanced presence on the surface is of importance in any potential applications. Angle-dependent XPS surface studies were conducted on polymer thick films to monitor surface segregation of the fluorinated component as a function of depth. Fluorine and the fluorine-containing constituents are surface enriched relative to carbon and oxygen from the acrylate portions of the polymers. This effect also occurs in the diblock copolymers, where the PFOA block prefers the polymer−air interface. Furthermore, this surface segregation is enhanced when the samples are thermally annealed. Also, the quantitative XPS data reveal other subtleties in the overall polymer structures, such as extent of chain branching in PFOA, PFOMA, and the diblock copolymers and the slight variations in average fluorine-containing side chain lengths in PTAN.

Surface orientation of hydrophilic groups in sulfonated poly(ether ether ketone) membranes

“…This segregation effect was found to be enhanced by annealing [29,51] and it is believed that the temperature is a crucial variable in affecting the surface morphology and composition in many cast membrane systems [51]. In our work, except for the SPEEK-HQ-70H top surface, this effect results in reinforcing the segregation of hydrophilic groups between the surface and the bulk, leading to a lower sulfur atomic concentration of the outermost surface than in the bulk.…”

Switching surface polarity: synthesis and characterization of a fluorinated block copolymer with surface‐active tert ‐butoxycarbonyl groups

“…In addition to these studies, such materials have been used recently as surfactants in supercritical CO 2 6 owing to their unusual character as a micelleforming amphiphile in non-polar solvents. 7 Many approaches exist for the incorporation of fluorinated blocks, but they generally involve either the living polymerization of fluorinated monomers, largely acrylates, 7,8 or the modification of block copolymers prepared by anionic polymerization. 2,9,10 Recently, a new family of polymers was described using a mild direct fluorination reaction, 9 but most other examples involve the attachment of readily available fluorinated acids 2,11 as described in this paper.…”

Adhesion performance and surface characteristics of low surface energy psas fluorinated by UV polymerization

“…Table 3 lists the binding energy of each sample. The peaks at 293 eV and 689 eV were assigned to C1s of CF 3 and F1s of CF 3 (the F1s curve is not shown in this figure) [24]. The 294 eV peak was detected with increasing amounts of TFMA.…”