Application of Nanoparticles and Nanotechnology in Packaging and Printing Industry (I)

[Abstract] The article describes the basic concepts and research content of nanotechnology, the characteristics of nanoparticle and the application of nanotechnology in the packaging industry.

[Key words] Nanotechnology; Nanoparticles; Packaging industry

Nanotechnology is the commanding height of the development of science and technology in the 21st century, and is the leading technology of the new industrial revolution. It will cause a change in the production methods in various fields and will also change the way of life and work of people in the future.

The basic concept of nanotechnology

Nanotechnology is based on nanoscience and studies the properties and applications of materials with structural dimensions in the range of 0.1 to 100nm, methods and means for manufacturing new materials, new devices, and new processes. Nanotechnology is based on the microscopic theory of physics and chemistry, using contemporary precision instruments and advanced analytical techniques as means, modern science (chaotic physics, quantum mechanics, mesoscopic physics, molecular biology) and modern technology (computer technology, The combination of microelectronics and scanning tunneling microscopy, nuclear analysis technology. In the field of nanotechnology, the boundaries between the various traditional disciplines have become blurred, and the disciplines are highly intersected and integrated.

The main contents of nanotechnology research are nanomaterials (study of any kind of materials composed of nanostructured units, by changing the size of nanostructured units, controlling the chemical properties of interiors and surfaces, controlling their combinations, and designing the properties and functions of materials. Nanodynamics (study of micromechanics and micromotors, using a new process similar to the design and manufacture of integrated circuits, placing sensors, motors, and various processors on a single silicon chip to form a system); Learning and nanomedicine (researching the interactions between biomolecules, studying the fine structure of phospholipids, fatty acid bilayer planar biofilms, and DNA, etc., and also using self-assembly methods to put parts or components into cells to form new materials); Nanoelectronics (including nanoelectronic devices based on quantum effects, optical and electrical properties of nanostructures, characterization of nanoelectronic materials, and atomic manipulation and atomic assembly).

Nanoparticle properties

Nanoparticles generally refer to particles having a size between 0.1 and 100 nm, have the following effects, and thus derive many properties that conventional solids do not possess.

(1) Surface effect: The particle diameter of the material is reduced to nanoscale, the number of surface atoms increases rapidly, and the chemical activity increases. The surface area, surface energy, and surface binding energy of the nanomaterial increase rapidly.

(2) Volume effect (small size effect): When the size of the nanomaterial is equal to or smaller than the de Broglie wavelength of the conduction electron, periodic boundary conditions will be destroyed, magnetic, internal pressure, light absorption, thermal resistance, Chemical activity, catalytic properties, melting point, etc., have greatly changed compared with ordinary crystal grains.

(3) Quantum size effect: When the size of a nanoparticle decreases to a certain value, the electron energy level near the Fermi level changes from a continuous energy level to a discrete energy level, so that the nanoparticle has high optical nonlinearity and specific catalytic properties. And photocatalytic properties.

(4) Macroscopic Quantum Tunneling: Microscopic particles have the effect of penetrating barriers.

(5) Optical effect: When the grain size of a metal material is reduced to the nanometer level, its color mostly becomes black, and the smaller the particle size, the darker the color, indicating that the nanoparticle has a strong light-absorbing ability.

(6) Electromagnetic properties: The atomic spacing in metal materials will decrease with the decrease of particle size. When the metal grains are in the nano category, their density will increase, resulting in a decrease in the electrical conductivity; the magnetic order of magnetic materials A fundamental change has also taken place. Ferromagnetic materials in the coarse-grained state can be transformed into superparamagnetic states when the particle size is less than a certain critical value.

(7) Chemical and catalytic properties: Due to the reduction in the particle size of nanomaterials, the surface atoms account for a large proportion, with strong adsorption and high chemical reactivity.

(8) HP relationship: When the grain size is reduced to the nanometer level, the strength and hardness of the material increase with the decrease of the grain size, which approximately obeys the classical Hall-Petch relationship.

(9) Thermal properties: When the size of the constituent phases is sufficiently reduced, the equilibrium phase relationship will be changed due to various elastic and thermodynamic parameters in the confined atomic system. After the supermicronization of solid materials, the melting point decreases; the specific heat capacity of nanomaterials is also larger than that of the same coarse-grained materials.

(10) Other properties: Metals are usually extended. When the crystal size is reduced to its own stress can no longer activate the source of dislocations, it becomes quite hard, and in this case the critical length, open the source of this dislocation Stress becomes greater than the yield stress of known metals.

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