Mechanical Characteristics And Application In Flexible Electronic Devices Of NanoAg/PDMS With Random Distribution

Polymer composites reinforced by short nano-Ag fibers have great application prospects in flexible electronic devices,medical devices,intelligent robots,aerospace and other fields due to their excellent mechanical and electrical properties.For example,the composite materials can be used as wires in a flexible electronic device,electrodes for flexible batteries,etc.,and these structures are required to have good stretchability and compression properties.Therefore,understanding the flexibility of the composite materials have certain practical significance.Randomly distributed polymer composites reinforced by short nano-Ag fibers bonded to a compliant substrate form a "film-substrate" structure,and the structure is generally studied as a whole.The changes in the length distribution,orientation distribution and radius distribution of the fibers filled in the composite materials will have a great influence on the elastic modulus and the flexural modulus of the composites,which will affect the mechanical properties of the entire structure.In this paper,the optimal distribution characteristics of fibers will be analyzed theoretically,and the relationship between elastic modulus,flexural modulus,wrinkling behavior,post-buckling behavior and fiber distribution characteristics of composites will be discussed.The influence of the length distribution,orientation distribution and radius distribution of the fibers on the elastic modulus and flexural modulus of the composites will be clarified.We will describe the fiber length distribution,orientation distribution and radius distribution by constructing suitable probability density functions.The expressions of elastic modulus and flexural modulus will be obtained by “lamination analogy method”,and the influence of fiber distributions on elastic modulus and flexural modulus will be discussed.The results show that the elastic modulus and the flexural modulus can be optimized when the fiber radius is normal distribution.The wrinkling behavior of short nano-Ag reinforced polymer composites on a compliant substrate will be analyzed.We will obtain the wavelength and amplitude of sinusoidal wrinkles as functions of the modulus and thickness of the substrate by minimizing energy method.It is found that under the equilibrium condition,the wavelength is independent of the initial membrane force and remains unchanged with the increase of the amplitude.The expression of critical membrane force,amplitude and wavelength of wrinkles will be derived,and study the effects of fiber distributions on these three indicators.The "island-bridge structure" is another way to increase the ductility of flexible electronic devices.The short fiber reinforced polymer composites used as "bridge" in the "island-bridge" structure can further improve the ductility of the structure.The influence of fiber distributions on the critical pre-strain of the substrate and the maximum strain of "bridge" and "island" will be discussed.It is found that the critical pre-strain of the substrate increases first and then decreases with the average fiber length,and decreases with the increase of the average fiber angle.The maximum strain of the "bridge" and "island" increase first and then decrease with average fiber length and average fiber radius,and decreases with the increase of the average fiber radius.This paper will study the mechanics of short-nono-Ag-fiber-reinforced polydimethylsiloxane composites(NanoAg/PDMS).The results of this paper can provide theoretical guidance for the application of the NanoAg/PDMS composites in flexible electronic devices.