Physical Chemistry 1

2011 Fall Semester Physical Chemistry 1

(CHM2201)

Why or What is Physical Chemistry? Chemistry is the study of the composition, structure, and properties of matter and of changes that occur in matter Physical chemistry is the branch of chemistry that establishes and develops the principles of the subject in terms of the underlying concepts and the language of mathematics – P. W. Atkins Physical chemistry is the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of physical laws and concepts – Wikipedia

Example 1 : Isotropic Conductive Adhesives (ICAs)

Ag nanoparticle

Silica particle

Dispersion Removal of solvents Mixing with epoxy

epoxy

ethanol Casting onto slide glass

Curing (130℃& 1hr, 160℃ &2hr)

Nanovoltmeter &

Current Source

4-point probe

!   Measurement of electrical conductivity

( by courtesy of Dr. Heesuk Kim (KIST))

Isotropic Conductive Adhesives (ICA): High electric conductivity and low thermal expansion coefficient

!   Electrical conductivity

Resistivity (log scale) vs. Ag/silica ratio (vol%)

Silica particles have the effect on electrical conductivity of epoxy/silver nanocomposites

Percolation threshold : 23vol% only Ag vs. 18vol% Ag with 10vol% silica particles

Experiments ( by courtesy of Dr. Heesuk Kim (KIST))

!  Thermo-mechanical Properties : Coefficient of thermal expansion

By adding silica nanoparticles, the thermo-mechanical properties are enhanced.

Experiments ( by courtesy of Dr. Heesuk Kim (KIST))

Silica Nano-particles

Silver Nano-particles

Perform Monte Carlo simulations and locate a percolating network of silver nano-particles

Simulation Snapshot

Simulation Model

The intermolecular interaction between silver NPs becomes more attractive

1.  Addition of silica nanoparticles of 5 vol% results in the increase of the attractive van der Waals interaction by about 0.1 kBT

2.  A slightly more attractive molecular interaction decreases the percolation threshold concentration significantly, thus enhancing the electric conductivity

Becomes more attractive!

R

Free energy between Silver NPs

Nam, Cho et al. APL 99, 043104 (2011)

Example 2 : The shape of red blood cells

Gerald, Wortis, Mukhopadhyay et al. PNAS, 16766, 99 (2002)

Observed

Deformability of red blood cells is critical to their ability to deliver oxygen to tissues. Stiffened red blood cells caused by the invasion of a protozoan result in severe pain and damage to tissues : the mechanism of Malaria

Red Blood Cells in “Equilibrium”

Predicted from Thermodynamics

Physical Chemistry

Quantum Theory & Spectroscopy

물리화학2, 특론

Equilibrium Thermodynamics & Chemical Kinetics

물리화학1, 3

Statistical Thermodynamics 물리화학특론