**3. Characterization of the Cu/LDPE composite films**

#### **3.1 Microscopy observation**

Optical microscopy was used to investigate the distribution of the Cu microparticles in LDPE. The polarized optical microscopy photos of different LDPE/Cu composites were exposed in **Figure 3**. The copper particles distribution in the composite films are relatively uniform at both low (8%) and high (16%) copper contents.
