In response to increasingly severe global energy challenges, energy conservation and consumption reduction have become key development directions in the building sector. The development of high-performance thermal insulation coatings, therefore, possesses considerable engineering importance and application value. SiO₂ aerogel has shown broad application prospects in the field of thermal insulation coatings due to its unique nanoporous structure and ultralow thermal conductivity. However, balancing thermal insulation and mechanical stability in SiO₂ aerogel coatings remains challenging, and related experimental teaching remains insufficient. On this basis, this study designed and implemented a comprehensive teaching experiment centered on SiO₂ aerogel thermal insulation coatings, incorporating the entire process of material preparation, performance testing, and formulation optimization into the teaching system. The goal is to improve teaching effectiveness while systematically investigating the key factors affecting the comprehensive performance of the coatings.

A systematic experimental scheme was established in this study, and SiO₂ aerogel composite thermal insulation coatings were prepared. First, an aerogel dispersion slurry was prepared by high-speed dispersion, achieving uniform dispersal and structural stability of the aerogel under controlled dispersion conditions. Second, titanium dioxide and various functional additives were introduced, and a stable coating system was constructed through low-speed stirring. Third, a mechanical performance evaluation system was established, including coating appearance assessment, cross-cut adhesion testing, and pencil hardness testing, while thermal conductivity was measured using a steady-state thermal conductivity analyzer. Finally, a four-factor, three-level orthogonal experimental design was introduced to systematically optimize and analyze emulsion dosage and additive ratios.

The results showed that the type of base emulsion, the mass fraction of SiO₂ aerogel, and the additive ratio considerably affected coating performance. Among the emulsion systems, that of styrene and acrylic exhibited excellent film-forming performance and structural stability, with a smooth and dense coating surface, adhesion reaching grade 1, and hardness reaching 2H. On the basis of an orthogonal experimental analysis, different factor combinations were found to have significant effects on coating appearance quality, adhesion, and hardness. Through comprehensive evaluation, the optimal formulation was determined as follows: styrene–acrylic emulsion 30 wt%, defoamer 1 wt%, film-forming additive 1.5 wt%, leveling agent 0.5 wt%, thickener 1 wt%, titanium dioxide 15 wt%, and aerogel aqueous dispersion slurry 51 wt%. Under this formulation, the coating surface was smooth and defect-free, with an adhesion grade of 1 and a hardness of 2H, demonstrating good overall mechanical performance. On this basis, the influence of aerogel content in the slurry on the overall coating performance was further revealed. Increasing the aerogel mass fraction from 0% to 5% reduced the thermal conductivity of the coating from 0.1942 W/(m·K) to 0.0654 W/(m·K), indicating a considerable improvement in thermal insulation performance. However, when the aerogel content exceeded the critical value of approximately 4%, the highly porous structure induced internal defects in the coating film, making the coating prone to cracking and reducing adhesion to grade 3. This outcome reflects the trade-off between thermal insulation performance and structural integrity.

This study verified the effectiveness and application potential of SiO₂ aerogel as a functional filler in building thermal insulation coatings, clarified the influence of aerogel content, matrix system, and additive ratio on the thermal and mechanical coating properties, and proposed a formulation design strategy guided by comprehensive performance optimization. At the teaching level, this experiment facilitated full-process training from formulation design, material preparation, and performance testing to data analysis, enabling students to deeply understand the structure–property relationship of nanoporous materials and effectively enhancing their practical skills, data analysis ability, and capacity to solve complex engineering problems. This teaching model integrates scientific exploration and high-level talent cultivation and thus has strong value for wider implementation.