## 2 Stability
### Factor That Influence Instability
Therefore, if the vulcanization of the MCF rubber occurs during the electrolytic polymerization process without surpassing this point, the electrical signal from the MCF rubber sensor becomes unstable when the piezoresistivity of MCF rubber sensor is examined. This refers to usage whereby a generated electric current is measured via the application of a voltage with any electric source. In the case of (3), we must consider the change of the electric current flowing in the MCF rubber based on its deformation. The change of the electric current of the MCF rubber by compression has been elucidated in previous studies [1, 2, 3]. In addition, this has been theoretically explained in other studies [5,24]. The relationship between the transmitted probability \(T\), which represents the electric current flowing in the MCF rubber and the thickness \(b\), is shown in Figure 15a in the Appendix A. The relationship between the dimensionless capacitance \(C^{*}\) and the thickness \(b\) is shown in Figure 15b in the Appendix A. \(T\) and \(C^{*}\) increase by enhancing \(b\). \(T\) is considered to be re-expression of the electric current \(I\), \(C^{*}\) applies to the capacitance \(C\), and \(b\) applies to the deformation quantity. The motion of electrons described by the tunnel theory is categorized as electron transfer in the field of complex chemistry. The mechanism of the electron transfer is divided into two types based on the distance among the particles of Fe\({}_{3}\)O\({}_{4}\) and Ni, and the molecules of polyisoprene: outer-sphere electron transfer reaction (OSETR) and inter-sphere electron transfer reaction (ISETR), as shown in a previous study [5]. Whether OSETR or ISETR is generated depends on the probability of the distance among the particles and molecules--OSETR takes place in the case of long distances and ISETR occurs for shorter distances. Decreasing \(b\) represents a contraction of the MCF rubber. As \(b\) becomes smaller, ISETR is dominant in the change of the electrical property of the MCF rubber due to the electric-chemical reaction. In contrast, as \(b\) gets larger, OSETR is dominant. As the distance among the particles and molecules is reduced by deformation of the MCF rubber, \(I\) and \(C\) increase as shown in Figure 15. The enhancement of and \(C\) are presented as \(\Delta I\) and \(\Delta C\), respectively. In the case of \(\Delta I\) and \(\Delta C\), we can obtain the results as represented by Equations (1)-(3), together with Equation (A3) in the Appendix A. The notion is that \(I\) represents the amount of electron transfer and that \(C\) represents the amount of counter ion created by an anionic acceptor A\({}^{-}\) and cationic donor D\({}^{+}\). A and D are generated by particles and molecules with semiconducting roles by mixing and electrolytic polymerization as shown in Equations (A4)-(A7) in the Appendix A, which has been presented in a previous study [5]. However, the reaction occurs from the right-hand-side to the left-hand-side by irradiation of electromagnetic waves of \(\gamma\)-rays, microwave, light, etc. In the case of OSETR, which implies that the distance among the particles and molecules is large, the net reaction from the right-hand-side to the left-hand-side does not occur practically. In the case of ISETR, which implies that the distance among the particles and molecules is small, the net reaction from the right-hand-side to the left-hand-side occurs practically. In the case of Equation (1), the voltage \(V\) increases with time. The amount of A\({}^{-}\) and D\({}^{+}\) is small because ISETR is dominant in the reaction as shown in Equations (A4)-(A7), due to the small distance among the particles and molecules. However, the amount of electron transfer is larger than that of the counter ion:  
\[|\Delta I|>|\Delta C| \tag{1}\]  
In the case of Equation (2), the voltage \(V\) with time is constant.