Nanoscale ThermodynamicsNanoscale Thermodynamics

John EnriquezJohn Enriquez

Chem. 5369 (Molecular Electronics)Chem. 5369 (Molecular Electronics)

ProfessorProfessor: Dr. Elizabeth Gardner: Dr. Elizabeth Gardner

UT-El Paso (Fall 2006)UT-El Paso (Fall 2006)

Brief OverviewBrief Overview

What is nano-thermodynamics and where did it What is nano-thermodynamics and where did it begin?begin?

Who is the first person to research this topic?Who is the first person to research this topic?

How is it being used today?How is it being used today?

Physical data and thermodynamic properties Physical data and thermodynamic properties regarding selected compounds found in many regarding selected compounds found in many nanoHUB presentations.nanoHUB presentations.

Compounds Found in Molecular Compounds Found in Molecular Electronic ArticlesElectronic Articles

While viewing selected presentations on While viewing selected presentations on the nanoHUB website, the same organic the nanoHUB website, the same organic compounds are used in almost every SAM compounds are used in almost every SAM procedure. Also, one metallic solid is procedure. Also, one metallic solid is used.used.

They are: Dodecanethiol, Ethanol, They are: Dodecanethiol, Ethanol, Tetrahydrofuran (THF), Ammonium Tetrahydrofuran (THF), Ammonium Hydroxide, and Gold.Hydroxide, and Gold.

What is Nano-Thermodynamics?What is Nano-Thermodynamics?

First, thermodynamics is the investigation of First, thermodynamics is the investigation of changes in energy coming from a physical or changes in energy coming from a physical or chemical reaction.chemical reaction.

Gibbs Free EnergyGibbs Free Energy

G = H – T(S)

The thermodynamic variables of enthalpy (The thermodynamic variables of enthalpy (H), H), entropy (entropy (S), and free energy (S), and free energy (G) are used in G) are used in the Gibbs free energy equation. the Gibbs free energy equation.

What is Nanothermodynamics?What is Nanothermodynamics?

Nano-thermodynamics studies these same changes.Nano-thermodynamics studies these same changes.

The two differences are chemical potential and an The two differences are chemical potential and an ensemble term.ensemble term.

G = H – T(S) + [Σ(μ·dn)] + (E·dN)

Nanothermodynamics connects Nanothermodynamics connects nanosystems to macroscale nanosystems to macroscale

thermodynamicsthermodynamics

What is Nano-thermodynamics?What is Nano-thermodynamics?

The chemical potential term, [The chemical potential term, [ΣΣ((μμ·d·dnn)] was )] was added by added by Gibbs in 1961Gibbs in 1961 The symbols The symbols μμ is the chemical potential and is the chemical potential and nn is the is the

amount in moles.amount in moles. Hill included the nano-thermodynamics term Hill included the nano-thermodynamics term

which is added at the ensemble level of the which is added at the ensemble level of the system, [system, [EE··ddNN].]. The variable The variable EE is similar to a system’s chemical is similar to a system’s chemical

potential. The variable potential. The variable NN is the number of individual is the number of individual systems in that one solution component.systems in that one solution component.

• An ensemble of An ensemble of NN equivalent and noninteracting small equivalent and noninteracting small systems is itself a macroscopic system.systems is itself a macroscopic system.

What is Nano-thermodynamics?What is Nano-thermodynamics?

Usefull in analyzing both experimental and Usefull in analyzing both experimental and theoretical equilibrium properties of theoretical equilibrium properties of nanosystemsnanosystems

Ex. Mean field cluster model of ferromagnetism (ref.6)Ex. Mean field cluster model of ferromagnetism (ref.6)

For a thorough treatment of the theory and For a thorough treatment of the theory and

derivations of the equation, see reference 4.derivations of the equation, see reference 4.

When did this idea begin?When did this idea begin?

The idea and the study of small systems at equilibrium The idea and the study of small systems at equilibrium can be traced back to Terrell L. Hill.can be traced back to Terrell L. Hill.

From 1961 to 1963, Hill researched these small systems From 1961 to 1963, Hill researched these small systems in great detail.in great detail.

Without being aware of it, he was researching ways to Without being aware of it, he was researching ways to connect macro-thermodynamic systems to nano-connect macro-thermodynamic systems to nano-thermodynamic systems.thermodynamic systems.

He published his results in 1962 and 1963, but little He published his results in 1962 and 1963, but little attention was given to it since it was based on theoretical attention was given to it since it was based on theoretical and statistical models. Nanoscience was not yet and statistical models. Nanoscience was not yet discovered.discovered.

New attention for an old topic?New attention for an old topic?

In recent years, research in nanoscience has In recent years, research in nanoscience has caught up with Hill’s theoretical work.caught up with Hill’s theoretical work.

In 2000, R.V. Chamberlin, who was investigating In 2000, R.V. Chamberlin, who was investigating ferromagnetism, was one of the first scientist to ferromagnetism, was one of the first scientist to use nanothermodynamic theory to explain his use nanothermodynamic theory to explain his findings.findings.

Hill reexamined nanothermodynamics as a Hill reexamined nanothermodynamics as a useful tool for nano-systems at equilibrium.useful tool for nano-systems at equilibrium.

Nanothermodynamics TodayNanothermodynamics Today

Professor Hill’s theories have been Professor Hill’s theories have been published in “Thermodynamics of Small published in “Thermodynamics of Small Systems.” (Ref. 8)Systems.” (Ref. 8)

R. Chamberlin was instrumental in reviving R. Chamberlin was instrumental in reviving interest in small system thermodynamics. interest in small system thermodynamics.

In 2005, A link was established between In 2005, A link was established between Hill’s nanothermodynamics and Tsallis Hill’s nanothermodynamics and Tsallis (nonextensive) thermodynamics. (Ref. 10)(nonextensive) thermodynamics. (Ref. 10)

Nanothermodynamics TodayNanothermodynamics Today

Since this area is still new, few articles Since this area is still new, few articles about this subject are available. about this subject are available.

Nanothermodynamics has the potential to Nanothermodynamics has the potential to be an important contributor to nanoscience be an important contributor to nanoscience and technologyand technology

Physical Data & Thermodynamic Properties of Physical Data & Thermodynamic Properties of Common Compounds Used in NanoscienceCommon Compounds Used in Nanoscience

Dodecanethiol (CDodecanethiol (C1212HH2626S)S)

M.W.M.W.: 202.4 g/mol: 202.4 g/mol

M.P.M.P.: unknown: unknown

B.P.B.P.: 143.5 : 143.5 °C at 15 mmHg°C at 15 mmHg

DensityDensity: 0.8435 g/cm: 0.8435 g/cm33 at 20 °C at 20 °C

SolubilitySolubility: Soluble in ethanol, : Soluble in ethanol, ethyl ether and chloroform. ethyl ether and chloroform. Insoluble in water.Insoluble in water.

Enthalpy (Enthalpy (H)H) = -253.3 kJ/mol = -253.3 kJ/mol

Entropy (Entropy (S)S) = 689.9 J/mol·K = 689.9 J/mol·K

Gibbs (Gibbs (G)G) = 78.01 kJ/mol = 78.01 kJ/mol

Ethanol (CHEthanol (CH33-CH-CH22-OH)-OH)

M.W.M.W.: 46.07 g/mol: 46.07 g/mol

M.P.M.P.: -114.1 : -114.1 °C at 760 mmHg°C at 760 mmHg

B.P.B.P.: 78.2 °C at 760 mmHg: 78.2 °C at 760 mmHg

DensityDensity: 0.7893 g/cm: 0.7893 g/cm33 at 20 °C at 20 °C

SolubilitySolubility: Miscible in water, : Miscible in water, ethanol, ethyl ether and ethanol, ethyl ether and acetone.acetone.

Enthalpy (Enthalpy (H)H) = -277.6 kJ/mol = -277.6 kJ/mol

Entropy (Entropy (S)S) = 160.7 J/mol·K = 160.7 J/mol·K

Gibbs (Gibbs (G)G) = -174.8 kJ/mol = -174.8 kJ/mol

Physical Data & Thermodynamic Properties, Cont.Physical Data & Thermodynamic Properties, Cont.

Tetrahydrofuran (THF): CTetrahydrofuran (THF): C44HH88OO

M.W.M.W.: 72.11 g/mol: 72.11 g/mol M.P.M.P.: -108.3 : -108.3 °C at 760 mmHg°C at 760 mmHg B.P.B.P.: 65 °C at 760 mmHg: 65 °C at 760 mmHg DensityDensity: 0.8892 g/cm: 0.8892 g/cm33at 20 °Cat 20 °C SolubilitySolubility: Soluble in water. : Soluble in water.

Very soluble in ethanol, ethyl Very soluble in ethanol, ethyl ether and acetone.ether and acetone.

Enthalpy (Enthalpy (H)H) = -216.2 kJ/mol = -216.2 kJ/mol Entropy (Entropy (S)S) = 204.3 J/mol·K = 204.3 J/mol·K Gibbs (Gibbs (G)G) = =

Ammonium Hydroxide: NHAmmonium Hydroxide: NH44OHOH

M.W.M.W.: 35.05 g/mol: 35.05 g/mol M.P.M.P.: -77 : -77 °C°C B.P.B.P.: 36 °C: 36 °C DensityDensity: Approx. 0.9 g/mL: Approx. 0.9 g/mL Solution Conc.Solution Conc.: 14.8 mol/L: 14.8 mol/L

Physical Data & Thermodynamic Properties, Cont.Physical Data & Thermodynamic Properties, Cont.

GoldGold (Element Symbol: Au) (Element Symbol: Au) Atomic NumberAtomic Number: 79: 79 M.W.M.W.: 196.96 g/mol: 196.96 g/mol M.P.M.P.: 1064.18 : 1064.18 °C°C B.P.B.P.: 2856 °C: 2856 °C Specific GravitySpecific Gravity: 19.3 at 20 °C: 19.3 at 20 °C SolubilitySolubility: Aqua Regia: Aqua Regia H (Fusion): 12.7 kJ/molH (Fusion): 12.7 kJ/mol H (Vaporization): 343.1kJ/molH (Vaporization): 343.1kJ/mol

ReferenceReference:: CRC Handbook of Chemistry CRC Handbook of Chemistry

& Physics, 2001-2002& Physics, 2001-2002 Helgeson, H.C.; Owen, C.E.; Helgeson, H.C.; Owen, C.E.;

Knox, A.M.; Richard, L. Knox, A.M.; Richard, L. Geochim. Cosmochim. ActaGeochim. Cosmochim. Acta, , 1998, 62, 6, 9851998, 62, 6, 985

ReferencesReferences 1. CRC Handbook of Chemistry & Physics, 2001-20021. CRC Handbook of Chemistry & Physics, 2001-2002

2. Helgeson, H.C.; Owen, C.E.; Knox, A.M.; Richard, L. 2. Helgeson, H.C.; Owen, C.E.; Knox, A.M.; Richard, L. Geochim. Cosmochim. Geochim. Cosmochim. ActaActa, 1998, 62, 6, 985, 1998, 62, 6, 985

3. Hill, T.L. 3. Hill, T.L. J. Chem. Phys. J. Chem. Phys. 1962, 36, 31821962, 36, 3182

4. Hill, T.L. 4. Hill, T.L. Nano LettersNano Letters, 2001, 1, 273, 2001, 1, 273

5. Hill, T.L. 5. Hill, T.L. Nano LettersNano Letters, 2001, 1, 111, 2001, 1, 111

6. Hill, T.L. 6. Hill, T.L. Nano LettersNano Letters, 2001, 1, 159, 2001, 1, 159

7. Hill, T.L.; Chamberlin, R.V. 7. Hill, T.L.; Chamberlin, R.V. Proc. Natl. Acad. Sci. U.S.A.Proc. Natl. Acad. Sci. U.S.A. 1998, 95, 1998, 95, 1277912779

8. Hill, T.L. 8. Hill, T.L. Thermodynamics of Small SystemsThermodynamics of Small Systems; Dover: New York, ; Dover: New York, 19941994

9. Chamberlin, R.V. 9. Chamberlin, R.V. NatureNature 2000, 408, 337 2000, 408, 337

10. Garcia-Morales, V., Cervera, J., & Pellicer, J. 10. Garcia-Morales, V., Cervera, J., & Pellicer, J. Physics Letter APhysics Letter A, , 2005, 336, 822005, 336, 82

AcknowledgementsAcknowledgements

Dr. Elizabeth GardnerDr. Elizabeth Gardner

Dr. Michael I. DavisDr. Michael I. Davis

My fellow classmates in Dr. Gardner’s My fellow classmates in Dr. Gardner’s Molecular Electronics course at UTEP, Molecular Electronics course at UTEP, UT- El Paso.UT- El Paso.