Fluorescent-Enhanced Radiative Cooling of Colored Cellulose Pulp for Thermal Management and Aesthetic Applications

Abstract

Cellulose serves as a vital building block in various applications, particularly in paper and paperboard industries, where pulp derived from cellulose-rich sources plays an essential role. However, the traditional pulp is often considered low-value due to its limited potential for innovation. For instance, conventional pulp retains a brownish color from residual lignin, which restricts its effectiveness in applications that require cooling properties. While bleaching processes can produce white pulp with enhanced solar reflectance, it does not meet the growing demand for colored cellulose products. This study presents a scalable solution that leverages fluorescence to create colored cellulose pulp, enabling the preservation of vibrant colors while mitigating thermal stress. By harnessing photoluminescence with Stokes shift, this approach reduces solar heating effects, achieving cooling powers of 50–130 W m⁻² and temperature drops of 7–11 °C under sunlight. Furthermore, as the fluorescence-treated process is fully compatible with large-scale manufacturing, this enhanced thermal management capability significantly expands the potential applications of cellulose-based materials across various industries.