Oil surface tension

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Looking for a low viscosity oil with a high surface tension. Does PAO 6 or mineral oil have a higher surface tension at room temperature? Any additives that could increase surface tension? Other types of oils that have higher surface tension? Any ideas on how to measure surface tension?
 
Originally Posted By: cpetroff
Looking for a low viscosity oil with a high surface tension. Does PAO 6 or mineral oil have a higher surface tension at room temperature? Any additives that could increase surface tension? Other types of oils that have higher surface tension? Any ideas on how to measure surface tension?

Absolutely, I used to do it all the time in college. You need a surface tensiometer.
 
Originally Posted By: cpetroff
Looking for a low viscosity oil with a high surface tension. Does PAO 6 or mineral oil have a higher surface tension at room temperature? Any additives that could increase surface tension? Other types of oils that have higher surface tension? Any ideas on how to measure surface tension?


When you say surface tension, do you mean oil film strength? This is what helps prevent metal-to-metal contact inside engines before oil pressure builds up.

I'm just not sure how the surface tension of an oil relates to its performance.
 
Originally Posted By: cpetroff
Does PAO 6 or mineral oil have a higher surface tension at room temperature?

No difference that could be discerned outside of a surface tensiometer.

Originally Posted By: cpetroff
Any additives that could increase surface tension?

Tackifiers should increase the surface tension.

Originally Posted By: cpetroff
Other types of oils that have higher surface tension?

Bar and chain oil would have a pretty stout surface tension

Originally Posted By: cpetroff
Any ideas on how to measure surface tension?

As mentioned above, surface tensiometer
 
Probably not on basics of surface tension is a function of cohesion while maintaining contact with a different surface is a function of adhesion, but perhaps someone like SOJ can chime in on the specific properties of tackifiers.
 
Originally Posted By: kschachn
Originally Posted By: cpetroff
Looking for a low viscosity oil with a high surface tension. Does PAO 6 or mineral oil have a higher surface tension at room temperature? Any additives that could increase surface tension? Other types of oils that have higher surface tension? Any ideas on how to measure surface tension?

Absolutely, I used to do it all the time in college. You need a surface tensiometer.

I think degree of curvature of a meniscus indicates something on a relative qualitative basis for surface tension without specific quantification IIRC.
 
Originally Posted By: MotoTribologist
Originally Posted By: cpetroff
Any additives that could increase surface tension?

Tackifiers should increase the surface tension.

If that is the case then it would bead up and become less prone to adhesion.
 
Originally Posted By: kschachn
Tackifiers make the oil cling but is that a direct correlation to surface tension?

It depends on the type of tackifier. Those that improve cohesive properties will increase surface tension. Those that improve adhesive properties, should either have no effect or decrease the surface tension.

I suppose "polymer" would have been better than "tackifier" since tackifiers are typically referred to as adhesion-increasing additives.
 
Originally Posted By: cpetroff
Looking for a low viscosity oil with a high surface tension. Does PAO 6 or mineral oil have a higher surface tension at room temperature? Any additives that could increase surface tension? Other types of oils that have higher surface tension? Any ideas on how to measure surface tension?

You can compare surface tension between oils, by droppin it in water at 25C and see the one that beads up faster and remains most floating is the winner.
 
Originally Posted By: Hammehead

You can compare surface tension between oils, by droppin it in water at 25C and see the one that beads up faster and remains most floating is the winner.


Yeh, right.

And you'll be quoting "bead-up-speed" and "floatingness" to how many decimal places of what?

I've seen behaviour of an oil droplet suggested as a measure of oil degradation, and tried to read up on it quite a while ago. IIRC the idea is that polar compounds are formed during degredation which lower the surface tension via their greater affinity with water. IIRC again

(a) It doesn't work very well with modernish oils because they can contain polar molecules when fresh.
(b) Quantifying it by measuring surface tension is the mother of all metric nightmares.
(c) Surface tension measurements form the basis of no operational industrial oil quality tests, at all.

But maybe I missed something, or there's been a breakthrough.
 
Last edited:
Originally Posted By: MotoTribologist
Originally Posted By: kschachn
Tackifiers make the oil cling but is that a direct correlation to surface tension?

It depends on the type of tackifier. Those that improve cohesive properties will increase surface tension. Those that improve adhesive properties, should either have no effect or decrease the surface tension.

I suppose "polymer" would have been better than "tackifier" since tackifiers are typically referred to as adhesion-increasing additives

I guess I still don't understand what you mean. For what purpose would you want to increase the surface tension of the oil?
 
Originally Posted By: cpetroff
Looking for a low viscosity oil with a high surface tension. Does PAO 6 or mineral oil have a higher surface tension at room temperature? Any additives that could increase surface tension? Other types of oils that have higher surface tension? Any ideas on how to measure surface tension?

Same question as above, why would you want to increase the surface tension of the oil? I would think that would be an undesirable property.

And viscosity isn't related to surface tension.
 
Originally Posted By: kschachn
Originally Posted By: MotoTribologist
Originally Posted By: kschachn
Tackifiers make the oil cling but is that a direct correlation to surface tension?

It depends on the type of tackifier. Those that improve cohesive properties will increase surface tension. Those that improve adhesive properties, should either have no effect or decrease the surface tension.

I suppose "polymer" would have been better than "tackifier" since tackifiers are typically referred to as adhesion-increasing additives

I guess I still don't understand what you mean. For what purpose would you want to increase the surface tension of the oil?

Well you'd be increasing the cohesiveness to make it "string". The increased surface tension is a side effect really. It all gets wonky once you have those polymers in there though. I don't think a tensiometer would even be able to accurately measure the "stringy" fluids surface tension.
 
Originally Posted By: Ducked
Originally Posted By: Hammehead

You can compare surface tension between oils, by droppin it in water at 25C and see the one that beads up faster and remains most floating is the winner.




1) And you'll be quoting "bead-up-speed" and "floatingness" to how many decimal places of what?

But maybe I missed something, or there's been a breakthrough.


1) PERCEPTION in comparison DROP BEHAVIOUR, UPON use of the senses like vision and time. I´m sure you can define a winner with that. That´s because the OP is Lacking the correct equipment to COMPARE NOT MEASURE (PLEASE read my post before atempt to criticize). So, would you have a better approach?
 
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