**1. Introduction**

ing the atomic interactions. Simulation showed various processes of plastic deformation in

**Chapter 5** presents different applications of atomistic and coarse-grain (CG) molecular dy‐ namics simulations to drug delivery systems (DDSs). An excellent detailed review of the modeling in this area is also presented. Different applications of drug delivery carriers, such as liposomes, polymeric micelles, and polymersomes using atomistic and CG molecular dy‐

The information from this book will be useful for engineers, technologists, researchers, and postgraduate students interested in the study of the whole complex of computer simulation based on the concept of molecular dynamics methods for the task of designing and produc‐

I would like to express my appreciation to all the contributors of this book. My special thanks go to the Author Service Manager, **Ms. Anita Condic**, and other staff at InTech pub‐

**Prof. Alexander Vakhrushev**

Head of Department Mechanics of Nanostructures Institute of Mechanics, Udmurt Federal Research Center Ural Branch of the Russian Academy of Sciences, Russia Head of Department Nanotechnology and Microsystems Kalashnikov Izhevsk State Technical University, Russia

lishing for their kind support and great efforts in bringing this book to completion.

the field of defects and allowed to establish the complex behavior of defects.

ing nanomaterials and nanosystems with controlled properties.

namics simulations, are investigated.

VIII Preface

One of the main tasks of the modern industrial revolution "Production 4.0" is the translation of all processes preceding the actual receipt of a new product in a digital representation. Forecasts for the development of this stage of production point to the ever-increasing value of computer modeling, the urgency of which will constantly increase. It is expected that computer modeling will be invested more financial and intellectual resources. This is especially relevant for one of the main tasks of the industrial revolution "Production 4," called "designing materials with controlled properties," which is the basis for the development of effective biotechnologies and nanotechnologies. A full and exact solution to this complex problem is impossible without considering the properties and processes of the formation of materials with controlled properties at the atomic and nanoscale of mathematical description and modeling.

However, specific feature of the physical processes in nanoscale systems is that the key phenomena determining the behavior of a nanoscale system in real time at the macroscale take place at small space and time scales [1, 2]. Many experimental and theoretical studies have shown that the properties of a nanoscale system depend not only on the properties of its constituent elements but also on the regularities of the spatial arrangement of the nanoelements in nanosystem and the parameters of the nanoelements interaction.

In this perspective, the molecular dynamics, which allows to describe the formation, evolution, and properties of the above-mentioned nanosystems in a sufficiently complete and precise manner, should become one of the methods for calculating and modeling modern

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

engineers and technologists. This is explained by the fact that molecular dynamics, being a powerful tool of scientific research, is increasingly becoming a full-fledged stage in obtaining new materials, creating a new technological process and designing a new product at the nanoscale level. This process was observed in the 1960–1980s of the last century with respect to the finite element method and led to the fact that this method is now being applied well and confidently by modern engineers and technologists in the creation of new materials and machines. We can expect that the process of industrial revolution "Production 4.0" method of molecular dynamics will be adopted as an instrument of engineers and technologists.

• matching of boundary conditions at the transition from one modeling scale to another

Introductory Chapter: Molecular Dynamics: Basic Tool of Nanotechnology Simulations…

http://dx.doi.org/10.5772/intechopen.79045

3

Molecular dynamics allows us to proceed correctly from the study of atomic and molecular processes by methods of quantum mechanics to the study of processes at the macrolevel by the methods of continuous medium mechanics. The main problem here is the matching of the

• the method of modeling the processes of nanosystem formation and theoretical analysis of

Based on the foregoing, the purpose of this book is to describe a number of problems in the modeling of nanosystems and a detailed exposition of the application of molecular dynamics methods to problems from various fields of technology: material science, the formation of composite molecular complexes, transport of nanosystems, etc. The book summarizes the research results of the authors in the field of modeling of various nanosystems: soft supramolecular nanostructures, nano-sized beams of single-crystal Cu, metallic nanosized crystals,

The study of the materials of this book can be the beginning of the reader's study of the whole

In addition, it should be noted that the research materials dynamics methods presented in the book can be the basis for the development of artificial intelligence methods in relation to the

To get more complete information about the methods of molecular dynamics and its significance in the overall complex multilevel task of modeling nanosystems and nanomaterials, the novice reader can get additional information from the list of literature. In this list of papers and books, the works [6–23] to modeling by methods of quantum mechanics, works [24–31]

1 Department of Mechanics of Nanostructure, Institute of Mechanics, Udmurt Federal Research Center, Ural Branch of the Russian Academy of Science, Izhevsk, Russia

2 Department of Nanotechnology and Microsystems, Kalashnikov Izhevsk State Technical

• the bridge connecting the various stages of multilevel modeling of nanosystems.

boundary conditions of the modeling problems at each space-time scale. Thus, we can distinguish two main functions of molecular dynamics:

drug delivery systems, and systems stabilized by hydrogen bonds.

problem "designing materials with controlled properties."

\*Address all correspondence to: vakhrushev-a@yandex.ru

complex of modeling based on the concept of molecular dynamics modeling.

to molecular dynamics, and works [32, 33] to mesodynamics are devoted.

when the problem variables are changed, • stochastic behavior of nanoscale systems.

their properties

**Author details**

Alexander V. Vakhrushev1,2\*

University, Izhevsk, Russia

However, this will only be the beginning of a deeper penetration of modeling into digital production. It should be noted that, at present, in modern scientific research methods of modeling, the molecular dynamics is usually the key element of a more complex and comprehensive multilevel mathematical modeling comprising multiple spatial and temporal scales [3–5]. The main stages of such a multi-level modeling of nanosystems are quantum modeling, molecular dynamics, mesomechanics and continuum mechanics.

The calculation of the configurations of a molecular formation, which are the constituents of a nanoparticle, is based on the quantum mechanics ("ab initio") methods of modeling. These methods give the most complete and precise presentation of nano-objects and take into account quantum effects, but they are very intensive computationally. At present, the use of the quantum mechanics methods for the calculation of nanoscale systems is limited to 1000–2000 atoms composing a nanoscale system.

The modeling of the coalescence of molecules into nanoelements can be performed by the molecular dynamics method. The method allows to consider systems containing up to 10 million atoms and more than that, but it does not take into account quantum phenomena.

The calculation of the movement of nanoelements and their coalescence is the task for mesodynamics. The characteristic feature of mesodynamics is the simultaneous use of the methods of molecular and classical dynamics.

It should also be noted that a number of phenomena, in particular, the phenomena taking place at the final stages of the nanoscale system formation, can be considered within the framework of continuum mechanics.

Each of the above methods has its own advantages and limitations. The use of any of the above methods of modeling or their combination for specific nanotechnology problems depends on the calculation accuracy required.

One can point to a number of problems of such modeling listed below:


engineers and technologists. This is explained by the fact that molecular dynamics, being a powerful tool of scientific research, is increasingly becoming a full-fledged stage in obtaining new materials, creating a new technological process and designing a new product at the nanoscale level. This process was observed in the 1960–1980s of the last century with respect to the finite element method and led to the fact that this method is now being applied well and confidently by modern engineers and technologists in the creation of new materials and machines. We can expect that the process of industrial revolution "Production 4.0" method of

molecular dynamics will be adopted as an instrument of engineers and technologists.

dynamics, mesomechanics and continuum mechanics.

1000–2000 atoms composing a nanoscale system.

of molecular and classical dynamics.

2 Molecular Dynamics

framework of continuum mechanics.

the calculation accuracy required.

• large number of variables,

However, this will only be the beginning of a deeper penetration of modeling into digital production. It should be noted that, at present, in modern scientific research methods of modeling, the molecular dynamics is usually the key element of a more complex and comprehensive multilevel mathematical modeling comprising multiple spatial and temporal scales [3–5]. The main stages of such a multi-level modeling of nanosystems are quantum modeling, molecular

The calculation of the configurations of a molecular formation, which are the constituents of a nanoparticle, is based on the quantum mechanics ("ab initio") methods of modeling. These methods give the most complete and precise presentation of nano-objects and take into account quantum effects, but they are very intensive computationally. At present, the use of the quantum mechanics methods for the calculation of nanoscale systems is limited to

The modeling of the coalescence of molecules into nanoelements can be performed by the molecular dynamics method. The method allows to consider systems containing up to 10 million atoms and more than that, but it does not take into account quantum phenomena.

The calculation of the movement of nanoelements and their coalescence is the task for mesodynamics. The characteristic feature of mesodynamics is the simultaneous use of the methods

It should also be noted that a number of phenomena, in particular, the phenomena taking place at the final stages of the nanoscale system formation, can be considered within the

Each of the above methods has its own advantages and limitations. The use of any of the above methods of modeling or their combination for specific nanotechnology problems depends on

One can point to a number of problems of such modeling listed below:

• variation of the problem variables at different scales of modeling,

• characteristic times of processes at different scales differ by orders of magnitude,

• multiscale nature and connectedness of problems,

• variation of scales both over space and in time,

Molecular dynamics allows us to proceed correctly from the study of atomic and molecular processes by methods of quantum mechanics to the study of processes at the macrolevel by the methods of continuous medium mechanics. The main problem here is the matching of the boundary conditions of the modeling problems at each space-time scale.

Thus, we can distinguish two main functions of molecular dynamics:


Based on the foregoing, the purpose of this book is to describe a number of problems in the modeling of nanosystems and a detailed exposition of the application of molecular dynamics methods to problems from various fields of technology: material science, the formation of composite molecular complexes, transport of nanosystems, etc. The book summarizes the research results of the authors in the field of modeling of various nanosystems: soft supramolecular nanostructures, nano-sized beams of single-crystal Cu, metallic nanosized crystals, drug delivery systems, and systems stabilized by hydrogen bonds.

The study of the materials of this book can be the beginning of the reader's study of the whole complex of modeling based on the concept of molecular dynamics modeling.

In addition, it should be noted that the research materials dynamics methods presented in the book can be the basis for the development of artificial intelligence methods in relation to the problem "designing materials with controlled properties."

To get more complete information about the methods of molecular dynamics and its significance in the overall complex multilevel task of modeling nanosystems and nanomaterials, the novice reader can get additional information from the list of literature. In this list of papers and books, the works [6–23] to modeling by methods of quantum mechanics, works [24–31] to molecular dynamics, and works [32, 33] to mesodynamics are devoted.
