PHIL 2015 Lecture Notes - Lecture 9: Hydrogen Bond, Minimal Surface, Sonication
6 May 2020
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H-bonds which are strong, this means each interaction is a thermodynamically favourable event, once a. Erg is a unit of energy, 1 erg=10 ^-7 joule. Also second way to define surface tension and it is obvious, in addition to definition in terms of energy, we can define this in terms of force since n is a unit of force. A=2lds there is a 2 since there are two phases thus dw = gamma2lds. So we have 2 definitions of surface tension and both are equilvalent, one is energy and one is in terms of force. Instead of deltaw the ratio deltaw/a, normalize for area and this is =gammals + gammal-gammas. Spreading coefficient(s) = -dw/a this is equal to gammas-(gammal+gammals) so we call it spreading coefficient. Initial value of s is =72. 8 (28. 9 + 35. 0) this is =8. 9 dyne/cm, s +ve so we have spreading final one of gamma value is = 62. 2 (28. 8 + 35. 0) and this is =-1. 6 dyne/cm.
