Contact angle changes

The total area above the first intrusion curve, A in Fig. 12.1, to the maximum intruded volume indicated by the horizontal dotted line, corresponds to the P-V work of intrusion, IFj. This work term consists of three parts, the first of which is the work of entrapment, W, corresponding to the area between curves A and B. The second contribution to IF. is the work, fV g, associated with the contact angle change from 0, to 0 ... 

The work associated with the contact angle change from to is... 

By adding the area of entrapped mercury, T, to A in the above equation, the work associated with the contact angle change, W g, becomes the work necessary to alter the contact angle over the entire length of the pore, not only that portion which extrudes. Thus, W g can be expressed as... 

After completion of extrusion and at the start of another intrusion process the entrapped mercury undergoes a contact angle change from... 

Figure 2. Contact angle changes with various liquids on a film of poly (methyl methacrylate) irradiated in air...

Figure 7.15. Contact angle changes with temperature and time during temperature rise for Au-30 at.% Si on monocrystalline a-SiC. The experiment was performed in an alumina chamber furnace under high vacuum (Drevet et al. 1993) [24].

Figure 8.2. Contact angle and work of adhesion of Ga on vitreous carbon versus temperature. A variation of900K leads to a contact angle change of only ten degrees. From data reported by N aidich...

Figure 18.5 Surface contact angle changes of PTFE with exposure time in an argon RF plasma 2 seem argon, lOOmtorr, and 7W RF.

Figure 18.6 Water contact angle changes on argon RF plasma treated PTFE surface with aging time in air 2 seem argon, lOOmtorr, 7W RF, 30 s treatment.

Figure 18.9 Surface contact angle changes of LTCAT Ar treated PTFE with varying (a) argon flow rate at 6.0 A arc current and (b) arc current at 1500 seem argon for 10 s exposure to a low-temperature cascade arc torch.

In LPCAT operation, the injection of a reactive gas into argon plasma torch can produce new reactive species through the energy transfer from argon neutrals as described in Chapter 16. Figure 18.12 shows the water contact angle changes... 

Figure 18.10 Surface contact angle changes of PTFE with exposure time in a low-temperature cascade arc torch at sample positions of 9 in. (in glow) and 14 in. (out of glow) from the torch inlet 1500 seem argon, 6.0 A arc current.

Figure 18.11 Surface contact angle changes of LTCAT treated PTFE film with aging time 1500 seem argon, 6.0 A arc current.

Figure 18.12 Surface contact angle changes of LTCAT treated PTFE (a) dependence on hydrogen feed rate at 6.0 A arc current, 1500 seem argon flow rate, and 1.0 min treatment, and (b) dependence on exposure time at 6.0 A arc current, 1500 seem argon flow rate, 20 seem hydrogen, 1.0 min treatment.

When samples are immersed in water a significant decrease of the contact angle of water is observed. The change from the solid line with open circles to the dotted line with closed circles indicates the extent of contact angle change. The extent of decrease was inversely proportional to the crystallinity of the sample, which indicates that the surface configuration change occurs mainly in the amorphous phase in the surface state, i.e., F atoms attached to the crystalline surface are immobile. 

Figure 30.9 Contact angle changes of water and a primer on the Parylene C surfaces with Ar LTCAT treatment time Ar flow rate 1000 seem, arc current 6.0 A.

Figure 32.20 Water contact angle change of closed system and flow system TMS polymer surfaces with the power input of argon and oxygen plasma posttreatment.

FIGURE 2,23. Schematic representations of oxide thickness change and contact angle change with HF dip time. After Kondoh et a/. ... 

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