Material Physics B
Group 5
Optical and
Thermal Properties
Azizah Marsha A
(5009221027)
Armansyah F
(5009231006)
Muhammad Baihaqi I. K .
(5009231095)
Rifqi Fadhillah H.
(5009231049)
Ramadhani Fauza U
(5009231146)
INTRODUCTION
Material characterization is essential in research and industry to understand the
structure, composition, and properties of materials. Spectroscopy identifies
molecular structures, thermal techniques like DSC, TGA, and DTA analyze thermal
changes, and chromatography methods such as HPLC and UPLC separate and
quantify compounds. These combined techniques enable accurate and
comprehensive analysis for applications in pharmaceuticals, advanced materials,
environment, and food.
PROBLEMS
OBJECTIVES
1. What are the working principles of each material
characterization technique (Spectroscopy, DSC,
TGA, DTA, HPLC, and UPLC)?
2. What are the differences in characteristics,
advantages,
and
limitations
of
each
characterization method?
3. How can each method be effectively applied in
material characterization?
1. To explain the basic principles of
spectroscopy, DSC, TGA, DTA, HPLC, and
UPLC techniques.
2. To assess the strengths and weaknesses of
each material characterization method.
3. To provide understanding of the application
of these techniques in various fields.
Spectroscopy
Define
Spectroscopy is the study of the interaction between matter and electromagnetic radiation. It is
used to analyze the structure, composition, and properties of substances by observing how they
absorb, emit, or scatter light (or other types of electromagnetic radiation) at different
wavelengths.
Various possible modes of interaction of
light photons in the medium
Reflection
Absorption
Transmission
Scattering
Reflection
Reflection is a phenomenon in which light that hits the surface of a material is reflected back, rather than being absorbed or
transmitted. The technique that utilizes this principle is known as reflectance spectroscopy, which is a method of measuring
the intensity of light reflected from the surface of a sample as a function of wavelength. Through this technique, researchers
can obtain important optical information such as the refractive index, absorption coefficient, and band gap of a material.
Reflection itself is divided into two types, namely mirror reflection (specular) which occurs on smooth surfaces, and diffuse
reflection (diffuse) which occurs on rough surfaces. The following is a picture of the types of spectroscopy.
snell law
Absorption
When light of a certain wavelength passes
through or strikes a sample, some of the energy
of that light can be absorbed by electrons or
molecules in the material, causing a transition
from a lower energy state to a higher energy
state. This process forms the basis of absorption
spectroscopy, one of the most important
techniques for analyzing molecular structure,
concentration of substances, and chemical
interactions. In this technique, an absorption
spectrum is produced by measuring how much
light is lost (absorbed) at each wavelength.
Scattering
Scattering is a process in which light that comes into contact with a particle or molecule is
not only reflected or absorbed, but also spread in various directions that occur due to the
interaction between electromagnetic waves and particles in the sample, which can be
atoms, molecules, or other small particles. Unlike reflection and absorption, scattering
provides information about particle size, internal structure, and interactions between
particles.
Transmission
In this context, transmission spectroscopy is a
technique that measures the intensity of light
before and after it passes through a sample, to
determine how much light is transmitted at
each wavelength. This information is then used
to calculate the absorbance or transmittance,
which can then provide insight into the
molecular
structure,
concentration
of
compounds, and optical properties of the
material.
Transmission
techniques
are
particularly common in UV-Vis and infrared (IR)
spectroscopy, where the transmitted signal is
converted into an absorption spectrum. The
more light is absorbed by a sample, the lower
its transmittance value.
Types of Spectroscopy based on
interactions and wave ranges
UV-VIS
FTIR
UV-VIS
UV-Vis spectroscopy measures the absorption of light by a compound in the wavelength
range of 200–800 nm. The following is the wavelength range and spectrum for UV-VIS
spectroscopy. When light hits a sample, electrons in the lowest orbital are excited to higher
energy orbitals. This absorbance depends on the electronic structure of the molecule. These
reactions generally occur in π → π* and n → π* bonds, which are common in organic
compounds with conjugated systems. Schematic of UV-VIS spectroscopy.
FTIR
FTIR measures the absorption of infrared signals by molecules in the range of
4000–400 cm⁻¹. Absorption occurs due to vibrations of chemical bonds such as
stretching and bending, which are typical for certain functional groups. With the
Fourier Transform technique, the time signal is converted into a frequency
spectrum that provides information on the structure of the molecule.
An interferogram is a graphical representation of light intensity as a function of the
optical path difference in an FTIR system. It reflects the interference pattern resulting
from the combination of two or more light waves of different wavelengths, such as λ
and 3λ. In FTIR, the interferogram is the raw signal collected before Fourier
transforming it to obtain the infrared spectrum. Each wave contributes to the overall
shape of the interferogram, which reflects a mixture of signals from different
frequencies.
Differential Scanning
Calorimetry (DSC)
Differential Scanning Calorimetry (DSC)
used to study the response of materials to
temperature changes
to determine properties such as:
glass transition temperature (Tg),
crystallization temperature (Tc), and
melting temperature (Tm).
Typical
Graph DSC
Picture of Typical Graph DSC
Picture of Typical Graph DSC, Second Heat
Typical
Graph DSC
Picture of Typical Graph DSC
Picture of Typical Graph DSC, Second Heat
There are 3 stages:
(shows the initial properties of the material, e.g. from the factory)
1. first heating: endothermic peak/melting peak at 128.65 C
2. cooling: exothermic peak/crystallization peak at 109.57 C
(the original properties of the material afterward)
3. second heating: endothermic peak/melting peak at 128.54 C
Thermogravimetric
Analysis (TGA)
Thermogravimetric Analysis
Thermogravimetric Analysis (TGA) is a technique that measures material weight changes
with temperature under a controlled atmosphere. It is used to study thermal stability,
decomposition, and oxidation, especially in polymer applications.
The reaction models of accelerating (1), decelerating (2) and
sigmoidal (3) when it is plotted into the weight loss curve
Schematic diagram of TG instrument.
Advantage and
Limitations TGA
Advantages of TGA:
Accurately measures mass changes with temperature and time.
Effective for analyzing thermal stability, composition, and decomposition.
Applicable to solid, liquid, and gel samples.
Limitations of TGA:
Results are sensitive to heating rate, atmosphere, and sample container.
Kinetic models can be difficult to apply to complex non-isothermal reactions.
Does not provide direct thermal energy data without additional techniques like DSC.
Application of
TGA
Determining moisture content and residual solvents in
materials.
Investigating how materials absorb moisture and
studying reaction rates.
Identifying decomposition temperatures and stability
ranges.
Deriving thermal properties like activation energy or
specific heat indirectly.
Investigating how materials absorb moisture and
studying reaction rates.
Differential Thermal
Analysis (DTA)
Differential Thermal Analysis
Differential Thermal Analysis (DTA) measures temperature differences between a sample
and an inert reference to detect thermal events like melting or crystallization. It reveals
endothermic or exothermic changes without mass loss during controlled heating.
A representation of the DAT Curve showing
exotherm, endotherm and base line changes
Schematic diagram of a differential
thermal analyzer (a) complete layout (b)
furnace part sharing continuous heating
of sample and standard
Advantage and
Limitations DTA
Advantages of DTA:
Accurately measures mass changes with temperature and time.
Effective for analyzing thermal stability, composition, and decomposition.
Applicable to solid, liquid, and gel samples.
Limitations of DTA:
Results are sensitive to heating rate, atmosphere, and sample container.
Kinetic models can be difficult to apply to complex non-isothermal reactions.
Does not provide direct thermal energy data without additional techniques like DSC.
Application of
DTA
Identification of Phase Transitions: Melting,
crystallization, etc.
Material Characterization: Metals, ceramics, and
polymers.
Quality Control: Helps in quality assessment of industrial
products.
In Pharmaceutical Industry: Identifies polymorphic
transitions in drugs.
CHROMATOGRAPHY
( HPLC & UPLC )
CHROMATOGRAPHY
Separation techniques for mixtures are based on the difference in component affinity
toward the stationary phase and the mobile phase.
ANALYTICAL
TECHNIQUES
Separation
Identification
Quntification
Of Compounds in Mixtures
MAIN
TECHNIQUES
High-Performance Liquid
Chromatography (HPLC)
Ultra-Performance Liquid
Chromatography (UPLC)
FIELD OF
UTILISTION
Pharmacy
Food
Environment
Forensics
HPLC
Aspect
UPLC
HPLC
UPLC
Column particle size
> 2 µm
< 2 µm
Operating pressure
≤ 6,000 psi
≤ 15,000 psi
Separation efficiency
Standard
Higher
Analysis speed
Moderate
Very fast
Higher
More efficient
Solvent consumption
High-Performance Liquid
Chromatography (HPLC)
Elution based on the interaction of compounds with
the mobile phase and stationary phase .
The result is in the form of a Digital Chromatogram.
Ultra-Performance Liquid
Chromatography (UPLC)
Analysis takes less time.
Improved resolution
Solvent-saving
The result is in the form of a Digital Chromatogram.
UPLC shows a significant increase in analysis speed and
material efficiency compared to HPLC
Bhardwaj, S., Vandana, A., Vijay, B., & Gupta, M. K. 2014. Ultra Performance Liquid Chromatography: A Revolutionized LC
Technique. International Journal of Drug Regulatory Affairs, 2(3), 83-87. https://www.ijdra.com
SUMMARY
This presentation discusses key material characterization techniques including
spectroscopy, DSC, TGA, DTA, HPLC, and UPLC. Spectroscopy examines how
materials interact with electromagnetic radiation through reflection, absorption,
scattering, and transmission to analyze structure and composition. DSC, TGA, and
DTA assess thermal properties such as melting, crystallization, and decomposition.
HPLC and UPLC are chromatographic techniques used to separate, identify, and
quantify compounds efficiently, especially in pharmaceutical and environmental
applications. Together, these methods provide a comprehensive understanding of
optical and thermal behaviors of materials.
REFRENCES
Bhardwaj, S., Vandana, A., Vijay, B., & Gupta, M. K. 2014. Ultra Performance Liquid Chromatography: A Revolutionized LC
Technique. International Journal of Drug
Hammer, A., 2013. Thermal analysis of polymers: selected applications. Columbus, Ohio: Mettler Toledo.
Li, R., Huang, J., et al., 2013. Rapid analysis of drug metabolites using ultra-performance liquid chromatography. Journal of
Chromatography B 927, 112-118.
Nguyen, D.T., Guillarme, D., et al., 2010. Improved method sensitivity in pharmaceutical analysis using UPLC technology. Journal
of Separation Science 33, 2465-2477.
Nováková, L., Matysová, L., Solich, P., 2006. Advantages of application of UPLC in pharmaceutical analysis. Talanta 68, 908-918.
Regulatory Affairs, 2(3), 83-87. https://www.ijdra.com
Nováková, L., Matysová, L., Solich, P., 2006. Advantages of application of UPLC in pharmaceutical analysis. Talanta 68, 908-918.
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