Excimer Laser Induced Surface Photochemical Reaction of 1,2-Diaminoethane with Poly(tetrafluoroethylene)

Abstract

Poly(tetrafluoroethylene) (PTFE or Teflon) is notable for its nonadhesive and nonreactive character. Successful surface photochemical modification of Teflon using liquid 1,2-diaminoethane and λ = 193 nm ArF excimer laser light was demonstrated. The surfaces were analyzed by X-ray photoelectron spectroscopy (XPS), atomic force microscopy, and liquid contact angle and gluing tensile strength measurements. Due to the photomodification the originally poor adhesive property of the PTFE surface was dramatically improved. Surfaces were glued by epoxy resin and the tensile strength of gluing increased by 150 times over that of the unirradiated samples. The surface was metalized electrolessly with silver on selected areas following patterned phototreatment. As a result of the photochemical reaction, hydrophilic and oleophilic property developed on the surfaces at the same time. The water and benzene contact angles decreased from 94° to 40° and from 31° to 0°, respectively. The removal of fluorine and the incorporation of both alkyl groups and nitrogen were identified on XPS spectra. The reaction cross section was determined from water contact angle and XPS results. It was found to be as high as (1.3−1.6) × 10-17 cm2. A radical or a photoinduced electron transfer mechanism is suggested to describe the photoreaction.

Surface properties and structures of diblock copolymer and homopolymer with perfluoroalkyl side chains

“…However, the surface free energy γ s (22 mJ/m 2 ) [11] of PTFE is far higher than the lowest one (6.7 mJ/m 2 ) evaluated for the hexagonal closest packed CF 3 group surface made of vapor-deposited C 20 F 42 [12]. Moreover, highly fluorinated polymers have disadvantages in the processing, physical properties, and cost [13][14][15]. For example, there are only a few solvents such as fluorinated solvents and supercritical carbon dioxide for dissolving them [16].…”

Surface properties and structures of diblock and random copolymers with perfluoroalkyl side chains

“…However, the surface free energy, γ , of PTFE is 22 mJ/m 2 [7], which is far higher than the lowest γ (6.7 mJ/m 2 ) for the hexagonal closest-packed CF 3 group surface made of vapor-deposited C 20 F 42 [8]. Further, these fully fluorinecoated polymers have disadvantages from the viewpoint of mechanical properties, processing, and cost [9][10][11]. In order to overcome them, copolymers with smaller amounts of fluorine-containing comonomers have potential applications as surface modifiers.…”

Effects of Film-Forming Conditions on Surface Properties and Structures of Diblock Copolymer with Perfluoroalkyl Side Chains

“…However, the γ s value of PTFE is 22 mJ/m 2 , which is far higher than the lowest one mentioned above. Further, these fully fluorinated polymers have disadvantages in their mechanical properties, processing, and costs. − To overcome these disadvantages, a successful approach is to attach perfluoroalkyl groups as side chains to copolymers with acrylate (methacrylate), − phenyl ester, siloxane, − styrene, − and isocyanate . Those polymers reportedly show high surface segregation of the perfluoroalkyl side chains, which causes the very low free energy on their surfaces, while maintaining the processability achieved by the other block components.…”