Creation of anti-frost micro-plastic texture surfaces enhancing thermal conductivity by carbon black containing in polyvinyl chloride

Abstract

Frost formation poses challenges in various sectors, impacting efficiency and safety. Active methods involve energy-consuming processes like heating, while passive approaches utilize protective coatings or hydrophobic surfaces to minimize frost aggregation. However, low thermal conductivity remains a concern. In previous research, lotus leaves inspired micro-meter-sized asperities were effective in controlling frost growth. Applying this concept to plastic, particularly low-cost PVC, raised challenges due to its low thermal conductivity. The study explores utilizing carbon black (CB) waste from hard coating processes to enhance PVC's thermal conductivity, forming a micro-plastic texture (MPT). The research investigates the influence of CB amount and AC voltage frequency on MPT features and thermal conductivity, aiming for a sustainable solution to address frost-related issues. Incorporating 0.9 vol.% CB into PVC solution under a 2 kV AC electric field (6 Hz) resulted in an extensively distributed MPT on the surface. This MPT, formed under the 6 Hz condition, exhibited no inplane bias, making it an ideal surface for preventing frost formation. Adding CB to PVC within the range of 0 to 2.1 vol.% and applying a 2 kV, 6 Hz AC electric field led to independent MPT formation at concentrations between 0.4 to 1.2 vol.%. Conducting cooling tests in atmospheric and vacuum conditions, we found that MPT with 0.9 vol.% CB displayed a thermal conductivity of approximately 0.19 kW/mK in atmospheric conditions, similar to aluminum alloy. However, with 1.2 vol.% or more CB, it decreased to about 0.15 kW/mK. In vacuum conditions, MPT with 1.2 vol.% CB exhibited a higher thermal conductivity of 0.063 kW/mK compared to the 0.055 kW/mK observed in MPT with 0 vol.% CB.