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IMPACT OF SURFACE CHEMISTRY, NUR IZZATY BINTI MOHD FUAD A18SC0221 -…
IMPACT OF SURFACE CHEMISTRY
SURFACES & INTERFACES
A boundary between a material and its surrounding environment and influence interactions with that environment.
At the molecular level, the surface atoms have a different chemical environment, fewer nearest neighbors, from that in the bulk.
These surface atoms with changed atomic and electronic structures exhibit high chemical reactivity.
This property makes surfaces and interfaces a favored medium for chemical and biological processes in nature and in technological applications
Modern surface chemistry is about molecular-level understanding and the control of surface chemical reactions.
Heterogeneous Catalyst Technology
A catalyst is an entity that accelerates a chemical reaction without being consumed in the process.
Heterogeneous catalytic reactions occur on the surface of solid catalysts and involve elementary surface chemical processes.
The acceleration of a chemical reaction is due to the high reactivity of surface atoms that facilitates bond breaking and bond rearrangement of adsorbed molecules.
Such as adsorption of reactants from a reaction mixture, surface diffusion and reaction of adsorbed species, and desorption of reaction products.
BENEFITS
Many complex catalytic processes evolved in the chemical industry
The petroleum industry with the development of catalytic cracking processes for naphtha refining
The development of catalytic processes for pollution control and prevention such as the three-way catalytic converter that reduces the pollutant emission from automobiles
Semiconductor-Based Technology
A transistor is a semiconductor device used to amplify or switch an electronic signal, and an integrated circuit contains millions of transistors etched out of a small semiconductor surface
Integrated circuits are in many modern electronic devices such as computers and cell phones.
After the invention of transistors, advances in epitaxial growth of silicon thin films, chemical vapor deposition, and surface etching techniques made the industrial large-scale manufacture of silicon-based integrated circuits possible
Anticorrosion Technology
High reactivity of surfaces may cause undesirable chemical (corrosion) or mechanical (wear and friction) processes, which lead to material and energy waste.
Uses various surface chemical processes to coat a material with a protective layer.
Protective layers consists of
metal oxides
(e.g., chromium oxide on stainless steels) or
polymers
(e.g., Teflon on pans) that are
inert in the environment
of their specific applications
Protective layer usually serves as a kinetic barrier to slow down corrosion process
The design of protective layers with enhanced stability requires surface chemistry investigations on the structures, growth, and breakdown mechanisms of the protective layers.
Surface analysis tools are used to elucidate the chemical composition and morphology of the protective layers, as well as the kinetics of their growth and breakdown in various corrosive environments
Lubricant Technology
A lubricant is a material confined between two hard surfaces in relative motion.
Its existence
helps reduce the friction
and
wear at the interfaces
Fluid-base lubricants
consist of viscous base stock and
additives
to enhance performance under heavy-duty and high temperature conditions
Solid lubricants
are layered materials such as graphite, tungsten disulfide, and molybdenum disulfide
used in high-temperature gas turbines and space applications where fluid-based lubricants are not stable because of vaporization.
NUR IZZATY BINTI MOHD FUAD
A18SC0221