Composition and solution properties of fluorinated block copolymers and their surface structures in the solid state

Abstract

A series of diblock copolymers composed of methyl methacrylate and 2-perfluorooctylethyl methacrylate (PMMA 144 -b-PFMA n ) with various PFMA block lengths were prepared by atom transfer radical polymerization (ATRP). The surface structures and properties of these polymers in the solid state and in solution were investigated using contact angle measurement, X-ray photoelectron spectroscopy (XPS), sum frequency generation (SFG) vibrational spectroscopy, surface tension and dynamic laser light scattering (DLS). It was found that with increasing PFMA block length, water and oil repellency decreased, the ratio of F/C increased with increasing film depth, and the degree of ordered packing of the perfluoroalkyl side chains at the surface decreased. When the number of PFMA block units reached 10, PMMA segments were detected at the copolymer surface, which was attributed to the PFMA block length affecting molecular aggregation structure of the copolymer in the solution and the interfacial structure at the air/liquid interface, which in turn affects surface structure formation during solution solidification. The results suggest that copolymer solution properties play an important role in structure formation on the solid surface. fluorinated block copolymer, surface structure, solution properties, air-liquid interface

Surface segregation of fluorinated moieties on poly(methyl methacrylate-ran-2-perfluorooctylethyl methacrylate) films during film formation: Entropic or enthalpic influences

“…When the peak at 2955 cm À1 appeared in the SFG spectra of the copolymer solutions, the contact angle values of the cast films were higher than those of corresponding spin-coated films. Therefore, the focus should be placed at the peak at 2955 cm À1 , which may be attributed to the asymmetric stretching vibration of the -CH 2 -connected to the perfluoroalkyl group [C 8 F 17 ] [30]. These results further to confirm that the conformations of copolymer chains at the solution-air interface were different when cyclohexanone and toluene were used as solvents.…”

“…When methyl methacrylate (MMA) and 2-perfluorooctylethyl methacrylate (FMA) block copolymer (PMMA-b-PFMA) film was prepared from its micelle solution with PMMA block as micelle corona and PFMA block as 0021-9797/$ -see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jcis.2010.05.042 micelle core, the segregation of fluorinated moieties was affected greatly by micelle stability and the solvent's evaporation rate [26][27][28]30]. The rapid solvent evaporation rate plus the good micelle stability resulted in forming a micelle-like aggregate structure at the film surface, on which the PMMA coronas are partly exposed to the surface [26][27][28].…”

Effect of block length on the self-assembly of end-capping perfluoroalkyl moieties on the polymer surface

“…The exposure of the micelles on the surface during film formation results in higher concentrations of non-fluorinated components at the surface [10,12] , and thus a relatively high surface free energy of the film. We proposed that fluorinated block copolymers with low fluorine contents might favor segregation of fluorinated moieties on the surface, which was confirmed by our previous work [13,14] .…”

Focus on polymer chemistry papers in Science in China Series B: Chemistry of the year 2009

“…Further copolymerization of tert-butyl acrylate (t-BA) from the surface of PS-g-TNTs was studied, illustrating the "living" characteristics of the surface-induced ATRP method used in this work. Yan et al also prepared well-defined polystyrene/silica hybrid nanoparticles by the ATRP method.Shen's group research interests are mainly on exploitation and development of new catalysts especially rare earth catalysts and methodologies in polymer synthesis [3][4][5][6]. Discrete ion-pair complexes [Ln(EDBP) 2 (DME)Na(DME) 3 ] [Ln = Er (1), Yb (2), Sm (3)] have been synthesized by the reaction between sodium salt of 2,2′-ethylidene-bis(4,6-ditert-butylphenol)(EDBPH 2 ) and Ln(BH 4 ) 3 ·3THF (Ln = Er, Yb, Sm) followed by centrifugation and recrystalization [3].…”

“…The polymerization of alkyl isocyanates catalyzed by rare earth chloride salen complexes/triisobutyl aluminum (Ln(H 2 salen) 2 Cl 3 ·2C 2 H 7 OH/Al(i-Bu) 3 ) at room temperature was also developed [4]. A series of diblock copolymers of poly(methyl methacrylate and 2-perfluorooctylethyl methacrylate) (PMMA-b-PFMA) with various PFMA block lengths were prepared by the ATRP, and their surface structures and properties were investigated by different techniques [5]. Tang et al [8][9][10] synthesized several kinds of hyperbranched polymers such as 1-decyl-1-methyl-2,5-bis{4-[(N,Ndiethylamino)methyl]phenyl}-3,4-diphenylsilole fluorogen, poly(1-phenyl-1-octyne)s containing different stereogenic and chromophoric pendants, and soluble poly(aroxycarbonylphenylene) etc.…”