1. Drying Methods of Aerogels and Their Differences

    Drying is the most critical step in aerogel fabrication. The goal is to remove solvents while preserving the 3D nanoporous network. Main methods include:
    （1）Ambient Pressure Drying (APD)
        · Low cost, but large shrinkage and uneven pore distribution result in degraded performance.
    （2）Freeze Drying (FD)
        · Removes solvent by sublimating ice; however, large pores or collapse may occur.
    （3）Supercritical CO₂ Drying (CO₂-SCD)
        · Mild conditions, decent pore retention, but requires multiple solvent exchanges and pore uniformity is limited.
    （4）Supercritical Ethanol Drying (EtOH-SCD)
        · Directly dries under ethanol supercritical conditions, eliminating capillary stress.
        · Produces the most uniform nanopore distribution, high porosity, large surface area, and excellent thermal stability.
        · Silica aerogels remain intact even at 500–1000℃.

    In summary: Aerogels prepared by EtOH-SCD have the most uniform nanoporous structure and best thermal stability, making them the top choice for high-end applications.

2.  IBIH is a global leader in using ethanol supercritical drying technology to mass-produce high-quality aerogels.
     IBIH employs advanced EtOH-SCD technology with proprietary large-scale horizontal drying equipment.
     Achieved industrial-scale production from lab to tens of thousands of metric square metres, with full intellectual property rights.
    Performance Highlights:
        · Porosity up to 85–99% with narrow pore size distribution.
        · Thermal conductivity as low as 0.016 W/(m·K).
        · Structural stability maintained at 500–1000℃
        · Visible light transmittance >80%, suitable for translucent  insulation.
        · Excellent compressive resilience and long service life.

Overall Evaluation:
    IBIH’s EtOH-SCD silica aerogels combine ultralow thermal conductivity, exceptional thermal stability, and optical transparency, representing the global top level. They are especially suited for high-end applications in energy-efficient buildings, new energy batteries, and aerospace.

1. Definition & Structure
    Aerogel: A three-dimensional nanoporous solid material produced by the sol–gel process, with extremely high porosity (80%–99%), large surface area, and a continuous solid skeleton filled with nanoscale pores of air.
    Aerosol: A dispersed system of solid or liquid particles suspended in a gas medium, such as fog, smoke, or spray. Essentially a two-phase system: dispersed particles/droplets + continuous gas phase.

2. Preparation
    Aerogel: Sol–gel method → Drying (supercritical or ambient) → Preserved porous network. Common types include silica aerogel, carbon aerogel, and polymer aerogel.
    Aerosol: Formed by mechanical atomization, chemical reaction, combustion, spraying, or condensation.

3. Physical Properties
    Aerogel: Solid, ultralow density (down to 0.001 g/cm³), ultralow thermal conductivity (as low as 0.013 W/m·K), high transparency, and tunable mechanical properties. IBIH's aerogel granules feature exceptional optical performance, with visible light transmittance exceeding 80%.
    Aerosol: Suspension with particle diameters from 1 nm to 100 μm, showing Brownian motion, light scattering, and sedimentation.

4. Applications
    Aerogel:
        （1） Building insulation (heritage restoration, near-zero energy buildings).
        （2）Aerospace (thermal protection tiles, Mars dust collection).
        （3）Batteries & electronics (thermal management, fireproof layers).
        （4）Petrochemical & industrial pipeline insulation.
        （5） Medicine & environment (drug delivery, oil–water separation).
    Aerosol:
        （1）Meteorology & environment (smog, climate studies).
        （2）Medicine (inhaled drug delivery).
        （3）Daily life (sprays, perfumes, insecticides).
        （4）Industry (spray coating, combustion, dust control.

5. Key Differences Summary

1. Definition

     The Sol–Gel Process is a versatile chemical method that transforms a system from a liquid (solution or sol) into a solid network (gel) through hydrolysis and condensation reactions.
        · Sol: A colloidal suspension of nanoparticles (1–100 nm) uniformly dispersed in a liquid.
        · Gel: As reactions proceed, particles aggregate and interconnect, forming a three-dimensional network that traps liquid inside the pores.

In essence, it is a liquid → colloid → solid porous network transformation.

2. Role in Aerogel Preparation

    Aerogel preparation involves three main stages:
        （1）Sol formation: Precursors such as metal alkoxides (e.g., TEOS) undergo hydrolysis and condensation to form a nanoparticle-containing sol.
        （2）Gelation: The sol gradually evolves into a three-dimensional gel network, with liquid still occupying the pores.
        （3）Drying: The liquid in the pores is removed by supercritical drying or ambient pressure drying, preserving the fragile gel network and yielding a highly porous solid — the aerogel.

    In aerogel synthesis, the sol–gel process is the foundation that builds the nanoporous skeleton, directly influencing pore size, surface area, and performance.

3. Other Applications
    Beyond aerogels, the sol–gel process is widely applied in advanced materials:

        · Optical & electronic materials: optical coatings, antireflective films, waveguides, semiconductor oxides.
        · Ceramics: high-purity, ultrafine ceramic powders and ceramic coatings.
        · Catalysts & adsorbents: porous oxides with large surface area for catalysis and pollutant removal.
        · Biomedical materials: drug delivery systems, bioactive glasses.
        · Protective coatings: high-temperature coatings, thermal barrier layers, and fire-retardant coatings.

Working Principles
    1. Nanoporous Thermal InsulationPorosity up to 80–99%, pore sizes (2–50 nm) smaller than the mean free path of air molecules.
        · Strongly suppresses:
        o Gas conduction
        o Solid conduction
        · Convection
    Result: Thermal conductivity (0.013–0.020 W/m·K) lower than still air.
    2. Delay of Thermal Runaway Propagation
        o Aerogel pads localize heat within the failed cell.
        o Delays propagation for several minutes, allowing BMS and safety systems to respond.
    3. Inorganic Fire-Resistant Barrier
        o Silica aerogels do not burn; at high temperature, they form a stable silica skeleton.
        o Acts as a "firewall", blocking flame and heat spread.
    4. Compression-Enhanced Insulation
        o Unlike conventional materials, aerogels become even better insulators under compression.
        o Maintains or improves insulation despite cell swelling or long-term mechanical stress.

    Silica aerogel is an ultralight inorganic material with a nanoporous network structure, featuring up to 99% porosity and thermal conductivity as low as 0.016 W/(m·K). With its unique thermal, acoustic, optical, and mechanical properties, it offers broad application potential across multiple industries.

    IBIH owns proprietary Ethanol Supercritical Drying Technology for aerogel production. Our products deliver high transparency, ultralow thermal conductivity, and exceptional thermal stability, enabling advanced solutions for building energy efficiency, industrial insulation, and next-generation applications.