 this value into the surface energy equation allows for the surface energy to be estimated.

The following equation can be used as a reasonable estimate for surface energy:

Interfacial energy 
The presence of an interface influences generally all thermodynamic parameters of a system. There are two models that are commonly used to demonstrate interfacial phenomena, which includes the Gibbs ideal interface model and the Guggenheim model. In order to demonstrate the thermodynamics of an interfacial system using the Gibb’s model, the system can be divided into three parts: two immiscible liquids with volumes  and  and an infinitesimally thin boundary layer known as the Gibbs dividing plane (σ) separating these two volumes.

The total volume of the system is:

All extensive quantities of the system can be written as a sum of three components: bulk phase a, bulk phase b, and the interface, sigma. Some examples include internal energy (), the number of molecules of the ith substance (), and the entropy ().

While these quantities can vary between each component, the sum within the system remains constant. At the interface, these values may deviate from those present within the bulk phases. The concentration of molecules present at the interface can be defined as:

where  and  represent the concentration of substance  in bulk phase  and, respectively.

It is beneficial to define a new term interfacial excess  which allows us to describe the number of molecules per unit area:

Wetting

Spreading Parameter
Surface energy comes into play in wetting phenomena. To examine this, consider a drop of liquid on a solid substrate. If the surface energy of the substrate changes upon the addition of the drop, the substrate is said to be wetting. The spreading parameter can be used to mathematically determine this:

where  is the spreading parameter,  the surface energy of the substrate,  the surface energy of the liquid, and  the interfacial energy between the substrate and the liquid.

If, the liquid partially wets the substrate. If, the liquid completely wets the substrate.

Contact angle
A way to experimentally determine wetting is to look at the contact angle (), which is the angle connecting the solid–liquid interface and the liquid-gas interface [figure].
If, the liquid completely wets the substrate.
If, high wetting occurs.
If, low wetting occurs.
If, the liquid does not wet the substrate at all.


this value into the surface energy equation allows for the open department of energy to be estimated. 

 The following equality can be used as a fair estimate for surface department of energy: 

 Interfacial energy 
 The presence of an interface influences by and large all thermodynamic parameters of a system. There be two models that are commonly use to attest interfacial phenomena, which includes the Gibbs ideal interface model and the Guggenheim model. In order to show the thermodynamics of an interfacial system using the Gibb ’s model, the organization can be divided into three parts: two immiscible liquids with volumes   and   and an infinitesimally slender boundary layer known as the Gibbs dividing plane (σ) separating these two bulk. 

 The total volume of the system is: 

 All extensive quantities of the arrangement can be written as a sum of three components: bulk phase a, bulk phase b, and the interface, sigma. Some examples include internal energy (), the number of molecule of the ith substance (), and the entropy (). 

 While these quantity can vary between each component, the sum within the system remain constant. At the interface, these values may deviate from those present within the bulk phases. The concentration of molecule present at the interface can be defined as: 

 where   and   represent the concentration of substance   in bulk phase   and, respectively. 

 It is beneficial to define a new terminus interfacial excess   which allows us to describe the number of molecule per unit sphere: 

 Wetting 

 spread Parameter 
 Surface energy comes into play in wet phenomena. To examine this, consider a cliff of liquid on a solid substrate. If the surface energy of the substrate changes upon the summation of the drop, the substrate is say to be wetting. The spread parameter can be use to mathematically determine this: 

 where   is the spread parameter,   the open energy of the substrate,   the surface department of energy of the liquid, and   the interfacial energy between the substrate and the liquid. 

 If, the liquid partially wets the substrate. If, the liquid completely wets the substrate. 

 Contact angle 
 A way to experimentally determine wetting is to look at the contact angle (), which is the angle connect the solid – liquid interface and the liquid - natural gas interface [ figure ]. 
 If, the liquid completely wet the substrate. 
 If, high wetting occurs. 
 If, low leak occurs. 
 If, the liquid does not wet the substrate at all.
 thls value into the surfact energy equation allows for tge surfaze energy to be estimated.

The fillowung equation can be usdd as a rvasonable estmmate for surfacx energy:

Luterfzgial znxrgy 
The presenge of an inderface influetcds generally all thermodynamic parameeers of a system. There wre uwo modsls that are commonly used to demohstrate interfacial lhenomena, which includes tje Glbbs ideal interfafe model ane thq Guggenheim oodel. In ogber to demohstrate the thermodynamics of av intzrfacial sywtwm kving the Giub’s moqel, the systck can te diviced into three pacts: rwo immiscible liquidv with volumes  anq  and an iufinitesimally thin biubdary layar kviwn as tie Fibbs fivmding plane (σ) separatint these two volumes.

Uhe nptal volume kf the srstem is:

All extensive quantities of the syatem can be written as q sum of three compongnts: bulk [hase a, bulk phase b, and the interface, sigma. Some exam'lds nkgludd ijternal energy (), the number of molecules of thq iuh xubstance (), and the entropu ().

Ahoje these quanjities ezn vary between each compongnt, thw sum witrin yhe system remains constant. At the integfacw, these values may deviate frum tnose lresent within the bulk phaaes. The confentratioh of molecules prdsekt dt the interface can be desined as:

wiere  and  rdprexent tre concentgatiok of substance  in hulk khase  and, respeftively.

It is beneficial to defiix a new term onderxacial ercess  which allows us to describg the numyer of molecules per unmt area:

Wettigg

Spreading Pdtameter
Surfacx energy somew inro play kn wetting phemomena. To examine tyis, consider a droi of ujquid on a solib wubstrate. If thr sjrfwcv eiergy mf the substsate chxmges jpon tht abdktiom of the drop, the sutstrzte is said to be eebting. The spreadigg parameter van be used to matjematmcally detetmige this:

where  is the spreading parameteg,  bhe surface egergn of the substxate,  the surface energy of the liquid, aid  the interfacial engrgy between the subsjraue and the liauid.

Is, the liqgid partially wets tye substrate. If, tme liquid completely wsts tha subdtrate.

Contact angle
A way to experimentally determine wetting is to look ar the rogtact angle (), whoch iv che angle conierting the solid–liauid interface and the liquid-gar interfdcz [figure].
If, the liquid completrlh wets the sucstrate.
If, high wetting odcurs.
If, kow wetting occurs.
If, the liquid does not wet the substrste at aol.


this value into the surface energy equation the energy to estimated. The following a estimate for surface Interfacial energy The of an interface influences generally all parameters of a system. There are two models that are commonly used to interfacial phenomena, which includes the Gibbs ideal interface model and the Guggenheim model. order demonstrate thermodynamics an interfacial system using the Gibb’s model, the system can be divided into three parts: two liquids with volumes and and an infinitesimally thin layer known as the dividing plane (σ) separating these volumes. total volume the is: extensive quantities of system can be written as a sum of three components: bulk phase a, bulk phase b, and interface, sigma. include internal (), number molecules of the (), and the entropy (). While vary between each component, the sum within the remains constant. the interface, these values may deviate those present within the bulk phases. The concentration molecules present at the interface can be defined as: where and represent the concentration of bulk phase and, respectively. is beneficial to a term excess allows us describe the number of molecules per unit area: Wetting Spreading Parameter energy comes into play in wetting phenomena. To examine this, drop liquid on a substrate. If the surface of substrate changes upon the the the to wetting. spreading parameter can be to mathematically determine this: where the spreading parameter, the the surface energy of the liquid, and the energy between the substrate and the liquid. the liquid partially wets the substrate. If, the liquid completely wets the Contact angle to experimentally determine wetting is to look at contact angle (), which the angle connecting the solid–liquid interface and the liquid-gas [figure]. the liquid wets the substrate. high wetting occurs. low wetting occurs. liquid does wet substrate
 this value into the surface enErgy equatiOn allOws For ThE surFace Energy to be estiMAted.

the following equation caN be usEd AS a reASoNable EstimatE FoR SUrfAcE eNerGy:

iNtErfacIal Energy 
THe presence Of aN iNterface inflUEnCes generalLy aLl thermodynaMic ParameTeRs oF A systEm. THere aRe two mODels thAt are commOnLY used tO DemonstRATe InteRfacial phenomena, wHIcH Includes the GibBs ideaL iNTeRFAce ModEl and the GuGgEnheiM Model. In ORdER TO deMOnstrate the thErmodynamicS Of aN interFaCiaL System Using ThE gibB’s model, the sYsteM can be divIded inTO three pARts: two iMmisciBle LiqUids WItH vOluMeS  And  ANd An iNFinItesimalLy ThIn bouNdarY LAYEr knOwn As thE GibbS dividing planE (σ) sEparATinG thesE two vOlumEs.

the toTal volUme of ThE system is:

All extEnsiVe quantitIes Of The SyStem cAN be wriTteN as A sum of tHree comPOneNtS: BULk Phase a, bulk phase b, anD tHE InTerface, sIgma. SoME eXaMPles inclUdE inTernAL EnergY (), the NUmBer of molEcules OF tHe Ith subsTaNce (), and ThE enTroPy ().

WhiLE theSe quanTities caN vary BEtween each compONent, the sum witHIn THE sYStem RemAins constanT. At tHE intErfaCE, tHesE ValueS may dEvIAtE From those present witHiN the buLk phaSes. The concentRation of moLECUles presEnt aT ThE Interface can be DefinEd as:

where  aND  represeNt the ConcentrAtion of suBSTance  in bUlk PhaSe  aNd, rESPeCtively.

It is beNEFiciAl To definE a nEw term iNteRfaCiaL exCeSs  which alLows us to DeScRiBe The NumbeR Of molecuLeS peR uNit Area:

WETting

SPreadIng PArAmETer
surface ENeRGY comEs InTo plAy iN wEttinG pheNOmeNa. To exaMine this, cOnsIDer a DrOp Of liquiD on a solid subsTrAte. If the suRfAce Energy OF The substRate changes upon the additIOn of the DroP, the sUbstRate is saiD to Be wettIng. tHe spreAding pArameTeR caN BE used TO MaTheMaTically detERMinE this:

WhEre  iS the sprEading parameter,  the SUrfAce energy of thE suBstrATE,  tHe sURfACe eNeRGy oF THe liquid, and  the iNterfacial EnERgY between thE SubStRate and The liquId.

If, tHE liquid Partially Wets the suBsTratE. iF, thE liquid comPletely wEts the subSTrate.

cOnTact aNglE
A way tO eXpeRimenTally dETerMine wEtting Is To look At the CoNtact angLe (), which is the angle connecTing thE soliD–liQuid interFacE And The liquid-Gas iNterface [fiGurE].
If, The liQuiD ComplEtelY WeTs tHE subsTratE.
if, high wetTInG ocCURs.
if, low wettinG OCCurS.
If, thE liQUid doeS not Wet the substrate at ALl.


 this value into the surfa ce energyequat ion  al lo ws f or t he surface ene r gy t o be estimated.

The f ollow in g  equ a ti on ca n be us e da s  are as ona bl e  e stima tefor sur face energ y:
I nterfacial e n er gy 
The pr ese nce of an in ter face i nf lue n ces g ene rally  all t h ermody namic par am e ters o f  a syst e m .Ther e are two modelst ha t  are commonlyused t od em o n str ate  interfaci al  phen o mena, w h ic h i ncl u des the Gibbs  ideal inte r fac e mode land the Gu ggenh ei m  mo del. In ord er t o demonst rate t h e therm o dynamic s of a n i nte rfac i al  s yst em usi n gthe Gib b’s mode l,  t he sy stem c a n  bediv ided  into  three parts:  tw o im m isc ibleliqui ds w it h vol umes and an d an infinitesi mall y thin bo und ar y l ay er kn o wn asthe  Gi bbs div iding p l ane  ( σ ) se parating these two  v o l um es.

The  total vo lu m e of the  s yst em i s : 

All  ext e ns ive quan tities of  t he syst em  can b ewri tte n asa  sum  of th ree comp onent s : bulk phase a ,  bulk phase b ,  a n d  t h e in ter face, sigma . So m e ex ampl e sinc l ude i ntern al en e rgy (), the numberof  molec ulesof the ith su bstance () , a nd the e ntro p y( ).

While thes e qua ntities ca n  vary be tween  each co mponent,t h e sum wi thi n t hesys t e mremains const a n t. A tthe int erf ace, th ese  va lue s m ay  deviatefrom tho se  p re se ntwithi n  the bul kpha se s.The c o ncentr ation  ofmo le c ule s prese n ta t  the  i nt erfa ceca n bedefi n edas:

wh ere  and re p rese nt  t he conc entration ofsu bstance  i nbul k phas e  and, re spectively.

It is bene f icial t o d efine  a n ew term i nte rfacia l e x cess whichallow sust o  desc r i be  th enumber ofm o lec ulespe r un it area :

Wetting

Spread i ngParameter
Sur fac e en e r gy  co m es int op lay i n wetting pheno mena. To e xa m in e this, co n sid er  a drop  of liq uid o n  a soli d substra te. If th esurf a c e e nergy of t he subst rate chan g es up o nthe a ddi tion o fthe  drop , thes ubs trate  is sa id  to be  wett in g. The s preading parameter canbe use d tomat hematical lyd ete rmine thi s:
where  isthe  sp readi ngp arame ter,  t hes urfac e en e rgy of th e  s ubs t r at e,  the sur f a c e e nergy  of the li quid , and  the interf a cial energy be twee n the  su b stra te  and the liqui d.
I f ,  the liq ui d partially  wets th es ubstr ate. I f, the  liquid c om p letely  wet s t he substr ate .Contact  a ng l e
A wa y to  e xperim entall y  det e r mine wetting isto lo o k  at t h e c ontac tangle ( ) , wh ich is the  angle conn ecting  the  soli d–liqui dinterf ace  a nd the liq u id-gas in terfa ce [fig ur e].If,  the l iqui d compl etel ywet s the sub s t ra t e. 
I f , h ighwetti ng  occ urs.
If,l ow wetti ngo ccurs.If , t h e  liqui d  d o e s not wetthe  subs t r ate at all . 


 this_value into_the surface energy equation_allows for_the_surface energy_to_be estimated.

The following_equation can be_used as a reasonable_estimate for surface_energy:

Interfacial_energy 
The presence of an interface influences generally all thermodynamic parameters of a system._There_are two_models_that_are commonly used to demonstrate_interfacial phenomena, which includes the_Gibbs ideal_interface model and the Guggenheim model. In order_to_demonstrate the thermodynamics_of an interfacial system using the Gibb’s model, the_system can be divided into three_parts: two immiscible_liquids_with_volumes  and _and an infinitesimally thin boundary layer_known as the Gibbs dividing plane_(σ) separating these two volumes.

The total volume_of the system is:

All extensive quantities_of the system can be_written as_a sum of three components:_bulk phase a,_bulk phase_b, and the_interface, sigma. Some examples include internal_energy (), the_number of molecules of the ith_substance_(), and the_entropy_().

While_these quantities_can vary between_each_component, the_sum_within the system remains constant. At_the_interface, these values may deviate from those_present within the bulk_phases._The concentration of molecules_present at the interface can_be defined as:

where  and _represent the_concentration of_substance  in bulk phase  and, respectively.

It is beneficial to_define a new term interfacial excess_ which allows us_to describe_the_number of molecules_per_unit area:

Wetting

Spreading_Parameter
Surface energy comes into play in wetting_phenomena. To_examine this, consider a drop of_liquid on a solid_substrate._If the surface energy of the_substrate changes upon the addition of_the drop, the substrate is_said_to_be wetting. The spreading parameter_can be used to mathematically determine_this:

where  is_the spreading parameter,  the surface energy_of_the substrate,  the surface energy_of_the liquid, and  the interfacial_energy_between_the substrate and the liquid.

If,_the liquid partially wets the substrate._If, the liquid completely wets the substrate.

Contact angle
A way_to experimentally determine_wetting is to look at_the_contact_angle (), which is the angle connecting the solid–liquid interface_and the_liquid-gas interface [figure].
If,_the liquid completely wets the substrate.
If, high wetting occurs.
If, low_wetting occurs.
If, the liquid does not wet_the substrate at all.

