# A Study on the Conductivity and Infrared Spectroscopy of Elastic Polymer Composite Materials
## 2 Materials and Methods
### Doping Concentration of Carbon and Electrical Conductivities  
When enough carbon atoms are close to each other as shown on Figure 3, they will form a continuous permissible energy level. This energy level can cause the electrons which were fixed on the valence band to move interatomically. It is not possible to distinguish which atoms these electrons belong to, which is called electron sharing. These electrons have both around atomic and communication movement characteristics, so they will split into the energy levels of many groups. The energy levels of each group are very close, so the energy levels turn into approximate continuity, while the composition of a particular band width, with this kind of energy level arranged as close-order belt shape, is called the energy band.  
An important consideration regarding electrode materials is the concentration of electronic states (DOS), which varies greatly for different forms of carbon. The high conductivity of metals results from the combination of a large number of atomic orbits to form bands with a high concentration of electronic states.  
Sole atoms that only have one energy level are those where the electron is bound on the energy level. When another atom is very close, the atoms interact and the energy level splits into two, resulting in a degenerated state. If there is one more atom approaching, it will split into three energy levels. As N's isolated atoms are brought together to form a solid, they will split into N's energy levels and become very close to each other. The electronic structure of each individual carbon atom is 1S\({}^{2}\)2S\({}^{2}\)2P\({}^{4}\), so a single carbon atom has two 1S states, two 2S states, four 2P states and higher energy state. Ns' carbon atoms will have 2 \(\times\) Ns' 1S states, 2 \(\times\) Ns' 2S states and 4 \(\times\) Ns' 2P states.  
Figure 4 is a solid model of the energy gap; the region between different energy levels without any electronics is called the energy gap or forbidden band. The width of the energy gap is the indicator of the difference between the insulator, semiconductor, and conductor. The carbon atoms of graphite's structure have very good electric conductivity because there is not an energy gap between the valence band and conduction band. Electrons move freely without changing energy, and metallic conduction follows [PERSON]'s law [11].  
Figure 3: The electronic structure of carbon atoms [10].  
When the distance between carbon atoms is smaller, then the carbon atoms will form a diamond lattice as Figure 5 shows. The 2S-2P energy level can be dispersed to two energy levels and possess 8 \(\times\)Ns' states. The top energy level is called the conduction band which has 4 \(\times\)Ns' states, and the bottom energy level is called the valence band, which also has 4 \(\times\)Ns' states. These two energy levels are separated by a very wide energy gap, a large band gap of more than 5 eV, so undoped diamond is normally electrically insulating and cannot be used as an electrode material [12]. But as with other large-band-gap materials, diamond can be made conductive by doping it with certain elements [13].  
Diamond electrodes that make use of the surface transfer doping effect have been named surface conductive diamond (SCD) materials [14]. The electroanalytical techniques for which diamond electrodes have been applied are called amperometric detection [15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35].