Surface properties of perfluoroalkylethyl acrylate/n-alkyl acrylate copolymers

Abstract

Wetting behavior of perfluoroalkylethyl acrylate (FA)/n-alkyl acrylate (AA) copolymers with the various length of side chains of the AAs is discussed from a standpoint of surface molecular mobility. The copolymerization reactivity ratio indicates that these polymers are random copolymers. The surface properties were studied by measuring dynamic contact angle, static contact angle and freeze-dried X-ray photoelectron spectroscopy, and the bulk properties by wide-angle X-ray diffraction and differential scanning calorimetry. The advancing contact angles for water were independent of side-chain length of AAs and were almost constant at 120°. We have attributed this phenomenon to the orientation of perfluoroalkyl groups (R f groups, C x F 2xϩ1 ) in air, which is independent of side-chain length of AAs. On the contrary, the receding contact angles showed small values of about 45°when n numbers below 8 and increased when n numbers above 12. This can be explained as follows. High wettability during the receding process at the n numbers below 8 results from regression of R f groups at the water-solid interface caused by minimization of the interface free energy. The low wettability during the receding process at the n numbers above 12 shows that R f groups cannot regress due to its crystallization. This mechanism is also supported by other measurements.

Phase behavior and surface tensions of amphiphilic fluorinated random copolymer aqueous solutions

“…It is known that the arrangement and orientation of fluorinated chain on surface depends on its chain length, long-chain fluorinated hydrophobe with m > 8 being in ordered and crystalline state whereas the short-chain hydrophobes are oriented randomly, and are in mobile state which results in the exposure of carbonyl group [3,17,19]. Possibly, when the long and rigid hydrophobes (m = 8) of single copolymer molecules are oriented randomly at the interface, they produce steric hindrance for the adsorption of other molecules, thereby reducing the adsorption of the copolymer but with decreasing hydrophobic chain length, the steric contribution would also be decreasing, thus resulting in the improved packing of the hydrophobes at the interface, and hence, lower surface tension.…”

“…There are many reports on the equilibrium surface properties [8][9][10][11][12][13][14] as well as dynamic surface properties [11,15,16] of fluorocarbon surfactants solutions, but to our knowledge, there are scarcity of report on the interfacial properties of amphiphilic fluorinated random copolymers, although there are some reports on the surface properties of the thin film of copolymer containing perfluoroalkyl and other hydrophobic side chains [3,[17][18][19]. In this context, we studied the phase behavior, equilibrium surface tension, and dynamic surface tension of aqueous solutions of some amphiphilic fluorinated random copolymers.…”

Fluorinated Hybrid Polymers by Copolymerization of Trialkylsilyl Methacrylate with Fluoroalkyl Methacrylate

“…The content of fluorine atoms on the surface might be higher in block-type copolymers and the surface character should be influenced by the content of fluorine atoms. 5 Contact angle measurements of the copolymers are summarized in Table III. Copolymer compositions of the samples were almost equal since the copolymers were synthesized by equimolar feed of each monomer with quantitative yields of copolymers.…”

“…Though radical copolymerization reactivity of fluoroalkyl acrylates with alkyl acrylates has been reported, 5 no report on the copolymerization of fluoroalkyl (meth)acrylates with silylalkyl (meth)acrylates is available.…”

Characterization of acrylic copolymer latex modified by fluorine, silicon, and epoxy resin

“…Because of high hydrophobicity and low surface tension, the fluorinated chains could accumulate at the surface during the latex film formation, and thus it was difficult to wet the latex films. When the polar water or apolar n-hexadecane contacted the surface, the fluorinated chains would reorient and rearrange with the environmental change [17], but cross-linking of VTES and F-51 can inhibit liquid penetration and surface reconstruction by immobilizing the surface molecules. Cross-linking would, therefore, decrease contact angle hysteresis.…”