Contact Angle and Wettability

[@InfinityLRDL]

Wow you explain this in a 10 min video while my professor took the whole class explaining this... very helpful:)

[@PolymerWorld]

Glad it was helpful!

[@raer5367]

Thanks for your video, the pictures are very nice and easy to learn

[@PolymerWorld]

Glad you like them!

[@PolymerWorld]

Correction- At 8:50 min. in case γsv < γls, then cos θ will be negative, and θ will be greater than 90 degrees (poor wetting) and if γsv > γls, cos θ is positive, and θ will be less than 90 degrees (wetting).

[@yhs10]

Thanks for the video, can we say higher molecular weight will have higher surface energy/tension? In a sense that if I paint HMW non-newtonian liquid on a wall it will NOT drip as much/easy as pure water?

[@PolymerWorld]

@@yhs10 The surface energy/tension will depend on chemical nature of the chain than its molecular weight. The reason of using HMW polymers for paint application is mainly because of its shear thickening behavior. Mostly polymers with high molecular weight show shear thickening behavior than polymers with lower molecular weight. Therefore when paint is applied, its viscosity increases and flow/dripping reduces .

[@baraaal-khateeb9511]

Iwas searching for this correction, Thanks

[@HamsaVarthan-ez8ty]

isn't it surface tension 'surface energy per unit area'. 9:05,kindly check here units are wrong

[@zeyadramadan8759]

I really appreciate you making this lecture. Well done.

[@PolymerWorld]

Thank you for the feedback!

[@tankajaehelapola3232]

Thank you i understood the concept very clearly

[@PolymerWorld]

Thanks for the feedback.

[@ssartaj90]

I guess if the surface energy of solid-vapor is more than solid-liquid, then theta will be less than 90 and thus the droplet wets the surface and vice versa for other equation you mentioned at 8:48

[@destinnguon4877]

This is very helpful! The inner molecules pull the outer molecules inward. The outer ones would LIKE to make their own bubbles so they can be surrounded, but the inner molecules prevent that. So I guess that higher surface tension = higher surface energy = the inner molecules are pulling harder inward than the outer molecules can resist = higher contact angle.

[@PolymerWorld]

high surface energy and high interfacial tension = low contact angle (more wetting)

[@townley1017]

Very intuitive

[@PolymerWorld]

Thank you for the feedback.

[@AnkitaSingh-nk1yq]

Wht is the example of contact angle for 180°

[@piyushgajraj3214]

It was much better than I expected , 😃 thankyou mam ❤️❤️

[@virenderbhardwaj3137]

8:30 WHAT DOES THOSE FORCES PHYSICALLY INDICATE, like which is the cause of them and on which they are acting?

[@SomebodySharp]

This was really helpful. thank you so much ❤

[@mbusogustavo4762]

Can we get a link to the follow up video?

[@physconic3843]

thank you ma'am very helpful

[@PolymerWorld]

Thank you for watching! Glad it was helpful.

[@Mkjsjenia]

Why we use ethyl cellosolve and formamide to make dyne solution??

[@utaritokn]

Great explanation,thnk you so much!

[@PolymerWorld]

Glad it was helpful!

[@vecchio1066]

I wonder whether it has ever occurred to this girl that Young's force diagram she so carefully reproduces leaves the vertical component of the force acting on the contact line uncompensated.

[@spreadpositivevibes...2263]

Reference book??..

[@whothe_n]

thankyou dr. helps me alot

[@thairsamer4770]

Thank you!!

[@منتظرالمعموري-ظ3ي]

thank u very much

[@PolymerWorld]

Thank you for watching our videos.

[@aman-zt9eh]

how unit of surace energy is J/m2? Surface energy is Surface tension * area so unit will be J??

[@PolymerWorld]

Surface tension is defined as the force parallel to the surface perpendicular to a unit length line drawn on the surface. The units of surface tension are Nm-1. On the other hand surface energy can be defined as the energy difference between the bulk of the material and the surface of the material. Surface energy is defined as the surface energy per unit surface area. The surface energy per unit area is identical to the surface tension measured. The units of surface energy are Jm-2

[@MetaSciencey]

How does air solid contact have an effect on liquid drop shape? Shouldn’t we only consider forces of surface tension due to liquid-solid and air-liquid interface only?

[@KHAVIANIKAS]

How to measure wettability

[@PolymerWorld]

Contact angle is a good indicator of the wettability of the surface/material.

[@DeepSpaceNetwork]

very good thanks!

[@yousra7918]

thank you :)

[@PolymerWorld]

Thanks for watching!

[@abhishekkumarjaiswal7397]

Thank you

[@PolymerWorld]

Thanks for watching!

[@fanishduttaojha2905]

Sound quality poor should be louder

[@mdbelalansari4031]

Thanks👌😊

[@Mehdiranjb]

🌹🌹

[@PolymerWorld]

Thank you.

[@ellylenky3462]

I really need a sub on this :( can somebody add a sub please? the accent is really hard to understand everything

[@PolymerWorld]

We will try to incorporate sub as soon as possible.

[@PolymerWorld]

Sub added....

[@yusufwaliyuddinazka8949]

Yes me too. The explanation is good enough and will be better with subs.

[@PolymerWorld]

@@yusufwaliyuddinazka8949 subtitle is added

[@retajehab2980]

Thank you!!

[@PolymerWorld]

Welcome!

[@emanabumadi3813]

Thank you!