Advanced Engineering Materials: A Review

Smart materials technology enables us to adapt to environmental changes by activating its functions. Multifunctional materials, sort of smart materials, can be activated by electrical stimuli so as to produce its geometry change or property change.

1. ADVANCED ENGINEERING MATERIALS By:- Parth Rajendra Lad Dwarkadas J. Sanghvi College of Engineering, Mumbai

2. Introduction An advanced material can be defined as any new or significantly improved material that provides a distinct advantage in performance when compared to conventional materials. Advanced Materials are materials that are specifically engineered to exhibit novel or enhanced properties that confer superior performance relative to conventional materials. Advanced materials means materials with engineered properties created through the development of specialized processing and synthesis technology, including ceramics, high value-added metals, electronic materials, composites, polymers, and biomaterials.

3. Classification Nano Particles 1.Carbon-Based Nanoparticles 2.Ceramic Nanoparticles 3.Metal Nanoparticles 4.Semiconductor Nanoparticles 5.Polymeric Nanoparticles Smart Materials 1. Piezoelectric materials. 2.Shape memory materials. 3.Chromogenic materials. 4.Magneto-restrictive materials. 5.Polymer Gel.

4. Nano-Particles 1.Carbon-Based Nanoparticles Carbon-based nanoparticles include two main materials: carbon nanotubes (CNTs) and fullerenes. CNTs are nothing but graphene sheets rolled into a tube. These materials are mainly used for the structural reinforcement as they are 100 times stronger than steel. CNTs can be classified into single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). CNTs are unique in a way as they are thermally conductive along the length and non-conductive across the tube. Fullerenes are the allotropes of carbon having a structure of hollow cage of sixty or more carbon atoms. These have commercial applications due to their electrical conductivity, structure, high strength, and electron affinity. 2.Ceramic Nanoparticles Ceramic nanoparticles are inorganic solids made up of oxides, carbides, carbonates and phosphates. These nanoparticles have high heat resistance and chemical inertness. They have applications in photocatalysis, photodegradation of dyes, drug delivery, and imaging. By controlling some of the characteristics of  ceramic nanoparticles like size, surface area, porosity, surface to volume ratio, etc , they perform as a good drug delivery agent. These nanoparticles have been used effectively as a drug delivery system for a number of diseases like bacterial infections, glaucoma, cancer, etc.

5. 3.Metal Nanoparticles Metal nanoparticles are prepared from metal precursors. These nanoparticles can be synthesized by chemical, electrochemical, or photochemical methods. In chemical methods, the metal nanoparticles are obtained by reducing the metal-ion precursors in solution by chemical reducing agents. These have the ability to adsorb small molecules and have high surface energy. These nanoparticles have applications in research areas, detection and imaging of biomolecules and in environmental and bioanalytical applications. For example gold nanoparticles are used to coat the sample before analyzing in SEM. This is usually done to enhance the electronic stream, which helps us to get high quality SEM images. 4.Semiconductor Nanoparticles Semiconductor nanoparticles have properties like those of metals and non-metals. They are found in the periodic table in groups  II-VI, III-V or IV-VI. These particles have wide bandgaps, which on tuning shows different properties. They are used in photocatalysis, electronics devices, photo-optics and water splitting applications. Some  examples of semiconductor nanoparticles are GaN , GaP , InP , InAs from group III-V, ZnO , ZnS, CdS , CdSe , CdTe are II-VI semiconductors and silicon and germanium are from group IV.

6. 5.Polymeric Nanoparticles Polymeric nanoparticles are organic based nanoparticles. Depending upon the method of preparation, these have structures shaped like nanocapsular or nanospheres. A nanosphere particle has a matrix-like structure whereas the nanocapsular particle has core-shell morphology. In the former, the active compounds and the polymer are uniformly dispersed whereas in the latter the active compounds are confined and surrounded by a polymer shell. Some of the merits of polymeric nanoparticles are controlled release, protection of drug molecules, ability to combine therapy and imaging, specific targeting and many more. They have applications in drug delivery and diagnostics. The drug deliveries with polymeric nanoparticles are highly biodegradable and biocompatible.

7. Smart Materials 1. Piezoelectric materials. They are several materials that can exhibit an electromechanical coupling that results in displacement of an material upon application of an electric field. This material produces a voltage when stress is applied and in reverse manner it produces stress when voltage is applied. There are two types of piezoelectric material, piezoceramic and piezostrictiors . Piezoceramic can elongate and compressed while piezostrictiors only exhibit elongation, independent of direction of applied electric field.

8. 2.Shape memory materials. The most common group of material that respond to a temperature change with shape change or elongation are shape memory alloys (SMA). These alloys mainly Titanium-Nickel alloys undergo a phase transformation up to temperature change. These are also called thermo-responsive material. They can hold different shapes at various temperatures. They can be deformed and regain original sharpened size.

9. 3.Chromogenic materials. These are the materials which changes their colour when electric or thermal change associated with it. There are three types of chromogenic materials and they are split into categories depending on what type of external stimuli triggers the change in colour. These three types of chromogenic materials are photochromic, thermochromic and electrochromic. Changes colour with a change of light.

10. 4.Magneto-strictive materials. Magnetostriction is the change of the material’s physical dimensions in response to changing its magnetization. This material will change its shape when it is subjected to a magnetic field. They can convert magnetic energy to kinetic energy or reverse. Most ferromagnetic materials are measurable magnetostriction.

11. 5.Polymer Gel. A polymer gel is a type of gel that consist of three-dimensional cross-linked polymer network that can undergo significant deformation. The gels can expand or shrink up to 1000 times in volume. These are also known as hydrogels. Some common type of polymer gels are Poly-vinly alcohols, Poly-acrylic acid and Poly-acrylo nitrile

12. Conclusion Today, the most promising technologies for lifetime efficiency and improved reliability include the use of advanced engineering materials and structures. Understanding and controlling the composition and microstructure of any new materials are the ultimate objectives of research in this field, and is crucial to the production of good smart materials. New and advanced materials will definitively enhance our quality of our life. This technology of advanced engineering materials by its nature, is a highly interdisciplinary field. Starting from the field of basic sciences such as physics, chemistry, mechanics, computing and electronics it also covers the applied sciences and engineering such as aeronautics and mechanical engineering .

13. THANK YOU!!!