Synthesis, Characterization, and Surface Morphology of Pendant Polyhedral Oligomeric Silsesquioxane Perfluorocyclobutyl Aryl Ether Copolymers

Abstract

The synthesis and characterization of solution processable, semi-fluorinated perfluorocyclobutyl (PFCB) aryl ether polymers possessing covalently bound pendant polyhedral oligomeric silsesquioxanes (POSS) cages is reported. The synthesis of POSS aryl trifluorovinyl ether (TFVE) monomers was accomplished by the condensation of commercial monosilanolalkyl-POSS with a TFVE-functionalized chlorosilane. POSS TFVE monomers were elucidated by 1H, 19F, 13C, and 29Si NMR spectroscopy, ATR-FTIR analysis, and elemental (C, H, and F) combustion analysis. Bulk thermal copolymerization of POSS TFVE monomers afforded random and block PFCB aryl ether copolymers functionalized with various POSS loadings. Quantitative monomer conversion was monitored by 19F NMR, which produced copolymer number-average molecular weights (M n) of (19.5−24.9) × 103 (in CHCl3 using polystyrene as standard) determined by gel permeation chromatography (GPC). Thermal properties of POSS PFCB aryl ether copolymers were evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Transmission electron microscope (TEM) analysis of spin cast optically transparent, flexible POSS PFCB aryl ether copolymer films revealed the presence of 5−20 nm-sized POSS agglomerates. Optical profilometer analysis of spin and drop cast film surfaces exhibited a modest increase in surface roughness of POSS PFCB aryl ether copolymers as compared to PFCB aryl ether homopolymers without POSS inclusion. The POSS copolymers exhibited a modest increase in hydrophobicity as measured by static water contact angle analysis. Synthesis, characterization, thermal analysis, and unique surface features of POSS PFCB aryl ether copolymers are discussed.

Synthesis of POSS-containing fluorosilicone block copolymers via RAFT polymerization for application as non-wetting coating materials

“…Even for pentablock copolymers with the same structure, the sample S2, which had a higher POSS percentage, showed a significant increase in the  r value in comparison with that of S3. It has been suggested that the increased surface roughness generated by POSS has a more important effect on WCA than surface composition does [38,39]. From Table 4, it could also be seen that the ice shear strength of S3 had the lowest value (247 ± 20 kPa) in all the samples, though they had a similar surface energy ca.…”

POSSⓇ in Tight Places

“…POSS are hybrid cage molecules related to silicones, with a chemical structure (RSiO 1.5 ) consisting of an inorganic core (SiO 1.5 ) and organic side groups (R). As a result of this structure, POSS can be incorporated into polymer systems in a number of ways including blending, grafting and copolymerization [3][4][5][6][7][8][9]. Many variations of POSS molecules can be synthesized; a few of greatest interest to the current srudy are illustrated in Fig.…”

“…1 Polyhedral oligomeric silsesquioxanes of interest to this study while its variety of organic periphery groups allows for reaction or other interactions with the host polymer. By modifying the type and ratio of the inorganic cage to the surrounding organic groups, the properties of POSS can span the gap from inorganic materials to organic substances The ease with which the organic periphery of POSS molecules can be modified is a major reason for the great interest in these materials as polymer modifiers, since the ability of an additive to be dispersed within a polymer matrix depend on matching structures and thermodynamic interactions [5,8].…”

“…Much research has gone into studying the effects of POSS which has been grafted onto [3,6] or copolymerized [3,5] into a polymer backbone, in which case these materials are simply interesting monomers. Less has been understood until recently about the behavior and interactions of POSS blended into a polymer system, and how to obtain successful property enhancements when using POSS as an additive.…”

Role of interface in dispersion and surface energetics of polymer nanocomposites containing hydrophilic POSS and layered silicates

“…Adding POSS to polymers can bring about significant improvements in the bulk properties of these polymers such as increased thermal stability, hardness, wear resistance, oxidative resistance, mechanical properties and decreased flammability and viscosity during processing [9][10][11][12][13][14][15][16][17][18][19][20]. There are also some limited studies on the surface hydrophobicity of POSS-based polymer nanocomposites [9,10,14,15,[18][19][20][21][22][23].…”