(185j) Copper-Carbon Nanomaterial Based Composite Coatings for Dramatic Improvements in Pool Boiling Heat Transfer

Innovations in electronic industries have led to miniaturization of electronic devices and risks of fire hazards arising from overheating of these devices has increased drastically. Thus, there is an alarming need of better thermal management solutions capable of extracting high heat from these devices. Pool boiling is the two-phase heat transfer process that offers effective and sustainable approach compared to the presently used single-phase cooling techniques due to absorption of large amount of latent heat during a phase change. Surface enhancement techniques such as micro/nano porous coatings and implementation of high thermal conductivity materials can assist in enhancing pool boiling performance further. In the recent years, several carbon nanomaterial-based coatings have been exploited for pool boiling applications due to their high thermal properties and surface areas. In our work, we have developed a variety of durable and robust coating techniques to enhance the heat transfer efficiencies to extremely high values.

We have implemented coating techniques such as multi-step electrodeposition and screen printing to develop novel graphene oxide-copper (GO-Cu), carbon nanotubes-copper (CNT-Cu), and graphene nanoplatelets-copper (GNP-Cu) based composite coatings owing to higher thermal properties of copper particles. Among these different coatings, we achieved highest ever reported performance for GNP-Cu composite coatings, representing an improvement of ~130% in heat dissipation and ~290% in efficiency when compared to pristine copper heater surfaces. The enhancement in heat transfer properties is attributed to the hierarchical pores which serve as the nucleation sites and influence the overall bubble dynamics that is responsible carry the heat between liquid and vapor phases.