End-functionalized polymers. 1. Synthesis and characterization of perfluoroalkyl-terminated polymers via chlorosilane derivatives

Abstract

Surface-active, perfluoroalkyl-terminated block copolymers were synthesized and characterized. These heterophase block copolymers were made by terminating a variety of living anionic polymerizations with a chlorosilane derivative containing a perfluoroalkyl group. This synthetic methodology was successfully applied to the anionic polymerization of styrene and 1,3-dienes. Perfluoroalkyl-terminated poly(olefin)s were obtained via hydrogenation of the unsaturated poly(diene) materials. Excellent control of the molar mass, molar mass distribution, and functionality was verified using conventional characterization techniques such as gel permeation chromatography, NMR, and elemental analysis. In addition, time-of-flight secondary ion mass spectrometry (TOF-SIMS) was employed to characterize the absolute molar masses and molar mass distributions and also the extent of functionalization.

Multi-end functionalised polymer additives synthesised by living anionic polymerisation—the impact of additive molecular structure upon surface properties

“…However, the sensitivity of living anionic polymerisation to functionality and impurities, limits 30 the use of functionalised initiators and it was concluded that any methodology to synthesise end functionalised polymers of the type described herein, would be more productive if an end capping strategy was adopted. To this end, a series of end capping agents were used, with one, two or three C 8 F 17 35 fluorocarbon (CF) groups (see figure 1). End capping agent 1CF (fig 1) is commercially available whereas 2CF and 3CF were synthesised according to previously reported procedures 49 .…”

“…Benzene (HPLC grade), toluene (HPLC grade), styrene (> 99%), isoprene (> 99%), hexane (HPLC grade), cyclohexane (HPLC grade) (all aldrich) were purified, dried and degassed by repeated freeze-pump-thaw cycles over calcium hydride 35 and unannealed films using water as the contact fluid, and all data quoted is the average of at least three and in most cases six individual contact angle measurements. A full statistical analysis of all the contact angle data has been carried out and the standard deviation for any individual data point varies 40 from approximately 0.25 to 1.25 in a few extreme cases but in the majority of cases varies between 0.3 and 0.7 -thus, an error bar representing a typical standard deviation of 0.5 has been added to figure 4 for illustrative purposes.…”

“…PS3CF additives were prepared in exactly the same fashion as 35 that described above for PS2CF additives. Thus, toluene (50 ml) and styrene (3.00 g, 0.03 mol) were distilled, under vacuum, into the reaction apparatus.…”

“…When these end capped polymers in their pure state -not as additives - 30 were cast into films, it was found that surface properties were (not surprisingly) strongly dependant on the number of CF groups. Furthermore, XPS and static contact angle measurements suggest surface saturation of endfunctionalized polymer chains in most cases when the number 35 of CF groups reaches between 8 and 16, Static contact angle measurements of these films when the surface is saturated with CF groups were between 110 and 115 o with water and between 53 and 56 o with dodecane. More recently we have devised a structure for an end functionalised polymer, with the 40 aim of developing the optimal molecular parameters for efficient surface modification when the functionalised polymers are used as additives in low concentrations.…”

“…For example, surface chemistries which promote adhesion, wettability, biocompatibility, chemical resistance and hydrophobicity are attractive for a 35 variety of applications. Low surface energy, highly fluorinated polymer surfaces are particularly appealing in terms of their liquid repellence, chemical inertness and low coefficient of friction and imparting these attributes to a surface can result in the polymers finding use in applications 40 such as anti-fouling finishes, biomedical devices, release coatings and filter media 1 .…”