Conductivity and mechanical properties of a single-helix carbon microcoil prepared by thermal chemical vapor deposition

In order to obtain the basic characteristics of a single-helix carbon microcoil (SH-CMC) with the diameter of ~1 mum for use as tactile sensor elements, the mechanical and electrical properties of a SH-CMC prepared by thermal chemical vapor deposition (CVD) were measured, and compared with the properties of a double-helix carbon microcoil (DH-CMC) having a diameter of about 5 mum. A SH-CMC can be extended up to 3 times its original length, and is not as good when compared to the 10 times extension of the DH-CMC. The conductivity of the SH-CMC is larger than that of the DH-CMC, indicating that the structure of the SH-CMC is more graphitized because the Fe catalyst used for the preparation of the SH-CMC is active than the Ni for the DH-CMC. The impedance |Z| and phase angle thetas results of the SH-/DH-CMC were excellent and corresponded with the model using the parallel components of the (R_p+L_p) and C_p as an equivalent circuit.