Poly surface tension studies

Surface tension studies of the most common fluorosilicone, poly(3,3,3-trifluoropropylmethylsiloxane) (PTFPMS), give unexpected results. Compared with (PDMS), PTFPMS has a higher liquid surface tension, a similar critical surface tension of wetting, and a considerably lower solid surface tension, as determined by water and methylene iodide contact angles and the method of Owens and Wendt (67). These results are summarized in Table X (7, 67, 72-74, 76, 77), in which PTFPMS is compared with two other fluorocarbon polymers, poly(tetrafluoroethylene) (PTFE) and poly(chlorotrifluoroethylene) (PCTFE). PTFE behaves like PTFPMS, whereas PCTFE behaves like PDMS. 

Surface tension studies, yielding results similar to the above, have been obtained on other combinations of polyelectrolyte/oppositely charged surfactant systems. These include poly-L-lysine/SDS (75), carboxymethylcellulose/alkyl TAB surfactants (76), and sulfonated polyacrylamide/DTAB (77,78) combinations. 

Surface Protection. The surface properties of fluorosihcones have been studied over a number of years. The CF group has the lowest known intermolecular force of polymer substituents. A study (6) of liquid and solid forms of fluorosihcones has included a comparison to fluorocarbon polymers. The low surface tensions for poly(3,3,3-trifluoropropyl)methylsiloxane and poly(3,3,4,4,5,5,6,6,6-nonafluorohexyl)methylsiloxane both resemble some of the lowest tensions for fluorocarbon polymers, eg, polytetrafluoroethylene. 

The poly-[HIPE] sample intrusion mercury porosimetry study reported in Figure 4.67 was carried out in a Micromeritics, Atlanta, GA, USA, AutoPore IV-9500 automatic mercury porosimeter.1 The sample holder chamber was evacuated up to 5 x 10-5 Torr the contact angle and surface tension of mercury applied by the AutoPore software in the Washburn equation to obtain the pore size distribution was 130° and 485mN/m, respectively. Besides, the equilibration time was 10 s, and the mercury intrusion pressure range was from 0.0037 to 414 MPa, that is, the pores size range was from 335.7 to 0.003 pm. The poly-(HIPE) sample was prepared by polymerizing styrene (90%) and divinylbenzene (10%) [157],... 

Four polymers with different surface compositions were used in this study—polystyrene (PS), poly(methyl methacrylate) (PMMA), polyacrylamide (PAM), and a poly(vinylidene chloride) (PVeC) copolymer (containing 20% polyacrylonitrile). Polystyrene has essentially a hydrocarbon surface, whereas the surfaces of poly (methyl methacrylate) and polyacrylamide contain ester and amide groups, respectively. The surface of the poly(vinylidene chloride) copolymer on the other hand will contain a relatively large number of chlorine atoms. The presence of acrylonitrile in the poly(vinylidene chloride) copolymer improved the solubility characteristics of the polymer for the purposes of this study, but did not appreciably alter, its critical surface tension of wetting. Values of y of these polymers ranged from 30 to 33 dynes per cm. for polystyrene to approximately 40 dynes per cm. for the poly(vinylidene chloride) copolymer. No attempt was made to determine e crystallinity of the polymer samples, or to correlate crystallinity with adsorption of the fluorocarbon additives. 

In many studies of wettability Zisman and coworkers have used the contact angles of a series of n-alkanes as a convenient means for determining for low energy solid surfaces [5,6,13,20]. In Figure 2 are plotted the cos 9 vs. 7lv° curves for the n-aUtanes on PMMA surfaces containing 0.5% additive I and 1.0% additive II. The critical surface tensions with additives I and n were 19 and 20 dynes per cm., respectively, representing a decrease of about 20 dynes per cm. from the value of obtained with the additive-free surface. Since the y values of 19 and 20 dynes per cm. are very close to that of 18 dynes per cm. reported by Fox and Zisman [l3] for the n-alkanes on poly-tetrafluoroethylene surfaces, it is apparent that a number of perfluoro-alkane groups are present in the outermost part of the surface phase with the principal axis of each carbon-carbon chain parallel to the surface. 

Extensively studied nonionic surfactants are PDMS / polyether block copolymers [31] and poly(ethylene oxide) substituted trisiloxanes [32-35]. They are able to achieve a maximum surface tension depression to about 21 mN/m and a low critical micelle concentration (CMC) [36], These siloxane surfactants can self-assemble into a variety of... 

BOL Bolten, D. and Tueik, M., Experimental study on the surface tension, density, and viscosity of aqueous poly(vinylpyrrolidone) solutions, J. Chem. Eng. Data, 56, 582, 2011. 

Materials used for the case study included PEDOT PSS poly(3,4-ethylenedioxythiop hene) poly(styrenesulfonate) 1.3 %wt in water (Sigma Aldrich), Dimethyl Sulfoxide (Fischer Scientific) and Surfynol (AirProducts). For drop cast conductivity and surface tension analysis, PEDOT PSS/DMSO(0-5 wt%) and PEDOT PSS/DMSO(0-5 wt%)/Surfynol mixtures were prepared at ambient conditions and allowed to mix in a sonication bath for 24 hours Samples were drop spread onto cleaned glass slides between the ends of conducting aluminium tapes. All samples were allowed to anneal in ambient conditions for 30 minutes at 130 °C. 

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