Synthesis of block copolymers having perfluoroalkyl and silicone-containing side chains using diazo macroinitiator and their surface properties

Abstract

ABSTRACT:The fluorosilicone block copolymers of poly(perfluoroalkylethyl acrylate)-bpoly(3-[tris(trimethylsilyloxy)silyl] propyl methacrylates) (PFA-b-PSiMAs) having perfluoroalkyl and silicone-containing side chains were obtained by three-step synthetic approaches. In the first step, hydroxyl-terminated poly(perfluoroalkylethyl acrylate) macromonomer (PFAM) was prepared by the free-radical polymerization of perfluoroalkylethyl acrylate and 2-mercaptoethanol. In the second step, PFAM initiator (PFAMI) was prepared from the condensation reaction of the hydroxyl-terminated PFAM and 4,4Ј-azobis-4-cyanopentanoic acid chloride (ACPC). ACPC was obtained from the reaction of 4,4Ј-azobis-4-cyanopentanoic acid and phosphorus pentachloride. In the third step, PFA-b-PSiMAs (BPFSs) were synthesized from the reaction of PFAMI macroinimer and SiMA. Fourier transform infrared spectroscopy and 1 H-NMR analyses verified that the syntheses of ACPC, hydroxyl-terminated PFAM, PFAMI, and BPFS were completed successfully. The intrinsic surface energies of BPFSs and their surface modification effects on poly(vinyl chloride) film were investigated by analyzing the surface free energies and atomic compositions of the outermost layer of the surfaces. BPFSs exhibit extremely low surface free energies of about 9.7-13.0 dynes/cm. It was confirmed that BPFS, having extremely low surface free energy, is preferentially enriched at the outermost layer of the surface of BPFS/poly(vinyl chloride) blend.

New poly(dimethylsiloxane)/poly(perfluorooctylethyl acrylate) block copolymers: structure and order across multiple length scales in thin films

“…Contact angle values with isopropanol were much lower and more sensitive than q w to the block copolymer composition. For example, q IP increased from 29 to 57 in going from Si(132)AF8 (14) to Si(11)AF8 (13). Isopropanol is in fact able to better discriminate between fluorine-rich and silicon-rich surface phases than other wetting liquids that are normally used to measure contact angles of polymer films.…”

“…In order to confirm the liquid-crystalline behavior and investigate the structure of the mesophases, WAXD analyses were performed on Si(132)AF8( 14), Si(11)AF8 (13) and Si(11)AF8 (21) which differed from each other in either the chemical composition or the relative length of the constituent blocks. In all cases, the diffraction patterns displayed one sharp wide-angle signal and up to three low-angle commensurate Bragg reflections indicative of a correlated layered structure (periodicity d ¼ 32.5 A), in which the perfluoroalkyl chains were arranged on a pseudo-hexagonal lattice (side of the hexagon a H z 5.5…”

“…Polymers and copolymers of diverse macromolecular architectures (linear, hyperbranched, graft, block) containing both siloxane chains and fluorinated moieties can match the material properties of the two individual components. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] While the former normally feature, e.g. chemical and thermal inertness, low glass transition temperature and low elastic modulus, and low wettability, typical of the latter are, e.g.…”

“…11,12 Within copolymerization methods, block copolymerization is especially a powerful tool to develop novel materials that combine in a synergistic way the advantageous properties of the constituent polymer blocks, namely the hydrophobic, soft nature of siloxane polymers and the hydrophobicity/lipophobicity and self-assembling capability of fluorinated polymers. 6,[12][13][14][15][16][17] The spontaneous organization of the perfluorinated segments, combined with the rigid rod-like nature of fluorocarbon chains, [19][20][21] can give rise to thermotropic liquid-crystalline mesophases. [22][23][24][25][26] Therefore, in such block copolymers, the interplay between the microphase separation of the chemically incompatible blocks and the liquid-crystalline organization of the perfluorinated side chains can result in highly hydrophobic, low adhesion surfaces, where the fluorinated block component is selectively and efficiently driven toward the surface of a polymer thin film.…”

Fluorine‐Containing Block Copolymers: Synthesis and Application as a Template for Nanocellular and Porous Structures Using Supercritical Carbon Dioxide

“…The molecular weights of these block copolymers are around 5000-50 000 and the molecularweight distribution is relatively narrow, the M w /M n values being 1.1-1.5. In addition, the iniferter radical polymerization method and diazo macroinitiator method were also reported (Guan and DeSimone, 1994;Kassis et al, 1996;Arnold et al, 2002;Kim et al, 1999;Bertolucci et al, 2004). Unfortunately, the resulting block copolymers were not well controlled in chain structure.…”