Page 173 - Handbook of Adhesion Promoters

166 Selection of Adhesion Promoters for Different

8.21 POLYTETRAFLUOROETHYLENE

The adhesive interface was formed between a conducting polymer/metal composite and a
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polytetrafluoroethylene substrate, resulting in a strong adhesion. Ag/polypyrrole compos-
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ite is absorbed inside the nano-sized pores of PTFE (see Figure 2.2). The composite
mechanically interlocks after solidifying, which causes strong adherence of the nanocom-
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posite.
Adhesion of PDMS to PTFE was negligible and it was not improved by application
of primer which was able to substantially increase adhesion to aluminum, silicon, and
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glass.
Permanent coating of hydrophobic polymers, such as polytetrafluoroethylene, is
often difficult, due to only weak interactions − typically based on van der Waals interac-
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tions − between substrate and coating. By activating the substrate using physical meth-
ods, such as plasma, corona or chemical etching methods, it is possible to overcome these
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adhesion problems. But, activated substrates lose these properties within a relatively
short period of time and rearrange back to their original states (prior to the activation treat-
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ment). The polyallylamine-grafted-perfluorophenylazide was successfully used as an
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adhesion promoter for PDMS on PTFE.
The polymer solution comprised of fluorinated terpolymers of ethylene/VDF/HFP
(Dyneon™ THV) in butyl acetate was used as an adhesion promoter for PTFE in the hol-
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low fiber membrane fluid transport device.
REFERENCES
1 Horvath, B; Kawakita, J; Chikyow, T, Appl. Surf. Sci., 384, 492-6, 2016.
2 Kersey, L; Ebacher, V; Bazargan, V; Wang, R; Stoeber, B, Lab. Chip, 9, 1002-4, 2009.
3 Zürcher, S; Dorcier, A; Fusco, S; Lopez, I; Tosatti, S, EP2236524, SuSoS AG, Oct. 6, 2010.
4 Jerman, RE; Brown, C; Hobbs, HD; Ruano, C; Wolanski, CS, US8540081, Markel Corporation,
Sep. 24, 2013.