Corrosion, erosion, and fouling by scale deposition are detrimental to heat‐exchanger tube at geothermal binary‐cycle power plants. In this work, polytetrafluoroethylene was blended in a polyphenylenesulfide matrix with different concentrations of multiwall carbon nanotube (MWNT) using the melt‐mixed method to reduce scale deposition on the metal surface. The prepared nanocomposites with different concentrations of MWNT were characterized by various properties such as morphology, hydrophobicity, electrical, thermal, and rheological properties. The morphology of nanocomposite was changed from smooth to nano‐pin‐like with the addition of MWNT. The varied concentration of MWNT led to differing hydrophobicity of nanocomposite. Increasing the loaded amount of MWNT in the nanocomposite led to decreased electrical resistivity up to 3.1 × 103 Ω cm because of percolation of the MWNT in the polymer matrix. In addition, we investigated the enhancement of thermal performance (10% of lower crystallization peak) of the prepared nanocomposite. These performance results indicate that the prepared nanocomposite can be widely adopted for use in high‐performance heat exchangers in geothermal industries.

Often times erosion, corrosion, and fouling by scale deposition are primary issues for geothermal-fluid-wetted process equipment. In particular, wet heat exchangers used in geothermal power plants must deal with scale deposition. Previously, a surface-coating of polytetrafluoroethylene (PTFE) was considered to provide a non-stick surface. However, intrinsically poor thermal conductivity of PTFE, along with its poor abrasion resistance and weak adhesion to metal substrate, turns out to be a serious concern for engineering use. In this paper, we report a fine-tuned nano-composite by incorporating PTFE/Carbon-nanotube (CNT) into the polyphenylene surfide (PPS) host matrix. PPS is a thermoplastic polymer exhibiting outstanding high-temperature stability, excellent flame resistance, and good chemical resistance. By adding PTFE/CNTs into a PPS matrix, a superhydrophobic surface can also be created by contemplating the chemical composition of the surface material and the cooperative effect of nano-micro structures at the surface. Furthermore, carefully engineered superhydrophobic surfaces can create so-called “dropwise condensation [1]” which can dramatically enhance steam condensation heat transfer. We report the performance results of such nanocomposites regarding steam condensation, along with other surface characteristics. It is our anticipation that, with proper treatment, PTFE/CNT blended PPS can be widely adopted for use in high performance heat exchangers in geothermal industries.