Diffusion of Shape Stabilized PEG-SiO₂ as a Driver for Producing Thermoregulating Facing Bricks.

Current building materials often lack sufficient thermal regulation, especially in fluctuating climates. Prior research has shown that phase-change materials (PCMs) can store and release thermal energy, but their integration into construction materials remains limited. No prior work had resolved how to embed PCMs into bricks without compromising structural integrity. This gap motivated the development of a form-stable PCM system. Traditional methods of PCM incorporation face challenges in maintaining shape and stability. The need for scalable, durable PCM-based building materials is evident. Existing studies focus on liquid PCMs, which can leak or degrade over time. This paper introduces a novel approach using a sol-gel method to stabilize PCMs. The study addresses the need for long-term thermal performance in construction materials.

The study aimed to develop a form-stable PCM integrated into facing bricks. The researchers focused on using PEG-SiO2 as the thermoregulating material. The motivation was to create a PCM that remains stable within the brick structure. The sol-gel method was selected to synthesize the PCM. The team wanted to evaluate how porosity affects PCM adsorption. They also sought to estimate the diffusion coefficient of the sol. The goal was to determine the maximum adsorption capacity of the bricks. The study aimed to assess the thermal performance of the resulting materials.

The researchers used a sol-gel method to synthesize PEG-SiO2. The sol was first adsorbed into porous bricks. Gelation was controlled to stabilize the PCM within the brick. The team tested bricks with varying porosities. Adsorption curves were generated to track sol uptake. Fick's second law was used to estimate the diffusion coefficient. Maximum adsorption capacities were measured for each brick type. The thermal energy storage capacity was evaluated using experimental data.

The study found that PEG-SiO2 could be incorporated into bricks at 15–110 wt.%. Adsorption increased with higher porosity in the bricks. The effective diffusion coefficient was calculated using Fick's law. The sol's adsorption rate varied depending on the brick's structure. Maximum adsorption capacities were recorded for each porosity level. The form-stable PCM improved thermal energy storage by up to 338%. The material demonstrated stable performance over an operational day. The results suggest that porosity significantly affects PCM integration.

The authors concluded that PEG-SiO2 can be effectively stabilized in facing bricks. The sol-gel method enabled controlled gelation within the brick pores. The study showed that porosity influences adsorption and diffusion rates. The form-stable PCM improved thermal energy storage capacity. The material can buffer indoor temperatures over an entire day. The results suggest that this method is scalable for construction use. The study supports the use of PEG-SiO2 in building materials. The findings may guide future PCM integration in construction.