At a glance, aerogel is used mainly for thermal insulation and thermal barriers, especially in silica aerogel blankets, panels, coatings, and composites. Beyond insulation, aerogels are also used or researched in environmental, energy, biomedical, and other advanced material applications.
Aerogel uses can be grouped into three main categories: insulation, surface-driven applications, and functional material applications. Across these areas, performance depends on measurable properties, including low thermal conductivity for insulation, high surface area for adsorption and catalysis, and tunable chemistry for more specialized or emerging uses.
For researchers and engineers, however, the practical question is not only what aerogel is used for, but which material characteristics explain whether an aerogel sample performs as intended in the lab or in service. This article looks at how aerogel applications connect to measurable properties, and how microscopy, spectroscopy, thermal analysis, and other characterization techniques help evaluate structure, chemistry, and performance.
What is aerogel? Aerogel definition before looking at uses
An aerogel is a highly porous, often nanoporous, solid material formed when the liquid in a gel is replaced with gas while much of the solid network is preserved. This gives aerogels very low density and high internal porosity.
Aerogels can be made from different chemistries, including silica, carbon, polymer, metal oxide, and hybrid or composite materials.
Silica aerogels are especially important commercially, particularly in insulation and thermal barrier applications. They are often used in engineered forms such as fiber-reinforced blankets, insulation panels, and coatings, where the aerogel provides low thermal conductivity and low weight while supporting materials help make it usable in practical formats.
Aerogels are typically produced by a sol–gel process, where a liquid precursor forms a connected gel network. The gel is then dried, often by supercritical or controlled ambient-pressure methods, to remove liquid while limiting shrinkage and pore collapse.
What is aerogel used for
Aerogels are used mainly in thermal insulation, surface-driven uses such as adsorption and catalysis, and functional systems such as energy storage, sensing, and biomedical scaffolds.
These uses can be grouped by the material properties that determine where an aerogel fits and how it performs:
- In thermal insulation and thermal barrier uses, the key drivers are thermal conductivity, density, pore/network structure, and thermal stability.
- In adsorption, catalysis, separation, and remediation, performance depends mainly on high surface area and accessible porosity.
- In energy, sensing, biomedical, and other functional systems, aerogels are often selected for broader functional or structural requirements, such as electrical or chemical functionality and mechanical behavior.
Thermal insulation and thermal barrier applications
Application fit: Aerogels are widely used for thermal insulation and thermal protection in buildings, industrial equipment, and demanding transport or battery systems where conventional insulation may be too bulky, heavy, or difficult to install. They are often supplied as blankets, panels, or coatings, depending on the application and installation requirements.
These insulation-led uses are among the most commercially established applications for aerogels today. Many commercial insulation products use silica aerogels, especially in blanket or composite forms, because silica aerogel materials combine very low thermal conductivity with mature processing and can be integrated into practical, durable insulation formats.
Performance drivers: The main performance driver is low thermal conductivity, especially where insulation must be thin, lightweight, or space efficient. Performance also depends on pore structure, density, thermal stability, and how the material behaves under heat, moisture, compression, handling, and service conditions.
Relevant material characterization techniques,available at Covalent, may include:
- Imaging and microscopy: digital optical microscopy, SEM, FIB-SEM, or Micro-CT for morphology, damage, reinforcement distribution, and internal defects.
- Density and porosity testing: gas pycnometry for skeletal density; gas adsorption porosimetry for surface area, pore volume, and pore-size characteristics.
- Thermal analysis: TGA, TMA, and DSC for mass loss, thermal stability, dimensional change, and thermal transitions.
- Surface chemistry and wettability: FTIR, XPS, and water contact angle for surface treatment, hydrophobicity, moisture resistance, and aging.
Adsorption, catalysis, separation, and remediation uses
Application fit: Beyond insulation, aerogels can act as functional porous materials in adsorption, water treatment, environmental remediation, and catalyst support applications where interactions with gases, liquids, ions, or reactive species are central.
Performance drivers: The most important material characteristics are high surface area and accessible porosity, especially where aerogels must adsorb target molecules, separate species, or support reactions, or interact with gases, liquids, ions, or reactive species. Surface chemistry, wettability, composition, and stability after exposure to moisture, heat, or other process conditions also affect performance.
Relevant characterization approaches may include:
- Porosity and permeability testing: gas adsorption porosimetry for surface area, pore volume, and pore-size features; capillary flow porosimetry for through-pores or permeability-related behavior.
- Spectroscopy and chemical analysis: FTIR, ATR-FTIR, XPS, and Raman spectroscopy for surface chemistry, functional groups, bonding, and chemical modification.
- Surface interaction testing: water contact angle, surface free energy, and zeta potential for wettability and liquid-facing behavior.
- Composition, phase, and oxidation-state analysis: EDS, EPMA, TXRF, ICP-MS, and ICP-OES for composition and contaminants; XRD for phase identification; and XAS for oxidation-state information.
Energy, sensing, biomedical, and functional systems
Application fit: Aerogels are also investigated for more specialized or emerging applications that are broader in chemistry and function than mainstream insulation. Such uses may involve silica, carbon, polymer, metal-oxide, or hybrid aerogels.
Functional material applications include active R&D areas such as energy storage, sensing, and biomedical scaffolds, where aerogel chemistry and pore structure are tailored for electrochemical, responsive, or biological performance.
| Functional application | Common aerogel chemistries | Key property and role |
| Energy storage | Carbon, graphene, and hybrid conductive aerogels | High surface area and interconnected pores can support charge storage and ion transport. |
| Sensors | Graphene, carbon, polymer, and hybrid aerogels | Lightweight porous networks with responsive electrical or surface properties can help detect strain, pressure, or chemical targets. |
| Biomedical scaffolds | Biopolymer-based aerogels such as cellulose, chitosan, alginate, or gelatin | High porosity and tunable pore structure can help support cell attachment and tissue integration. |
Table 1. Examples of Aerogel Chemistries and Key Properties in Functional Material Applications
These examples show how aerogel chemistry and pore structure can be tailored for different functional requirements, from electrochemical performance to biological compatibility and sensing response.
Performance drivers: The main performance driver is application-specific functionality, which may mean electrochemical performance, sensing response, scaffold structure, or acoustic behavior. depending on the system. Other drivers include phase or crystallinity, surface chemistry, electrical or chemical functionality, mechanical behavior, sample-to-sample consistency, and durability in service.
Relevant characterization approaches may include:
- Structure and chemistry analysis: XRD/Raman for crystallinity or structural changes; XPS/XAS for surface chemistry or oxidation state; NMR for molecular or local structure.
- Microscopy and nanoscale imaging: SEM, AFM, TEM, or FIB-SEM for morphology, defects, interfaces, and local structure.
- Optical, electronic, and thin-film testing: UV-Vis-NIR, 4-point probe, or spectroscopic ellipsometry for optical, electronic, conductive, or thin-film systems.
- Mechanical and thermomechanical testing: nanoindentation, tensile testing, DMA, rheology, or TMA for stiffness, damping, dimensional behavior, and durability.
Across these applications, aerogel performance depends on more than one property. For each application, characterization helps identify which material characteristics control performance under the relevant service conditions.
How Aerogel Structure and Chemistry Control Properties and Performance
Aerogel performance depends on how structure, chemistry, processing history, and final form affect the material, as well as how it is handled, installed, or exposed in service.
Although aerogels share a porous architecture, differences in composition, density, pore structure, surface chemistry, and product form help explain why one aerogel may suit insulation while another is better suited to catalysis or sensing — or why a sample may not perform as intended.
These characteristics are typically tuned during processing, including precursor selection, gelation, drying, and post-treatment.
For example, silica aerogels used for insulation typically rely on finer, relatively uniform mesopores (~10–50 nm) to help suppress heat transfer, whereas remediation aerogels may use a broader pore size range (~10 nm to >1 micron) to improve mass transport, surface access, and uptake. These differences can be tuned during sol–gel processing by adjusting water content, catalyst type and pH, and sometimes additives or templates.
The main variables include composition and aerogel type, density and pore structure, surface chemistry, and final form. Composition sets the broad performance envelope; pore structure affects thermal behavior, diffusion, and access to internal surfaces; surface chemistry controls interactions with moisture, gases, liquids, and reactive species; and final form affects handling, durability, and service suitability.
Each variable can be investigated using a relevant set of characterization techniques. Table 1 summarizes the main material features that influence aerogel performance and the characterization approaches commonly used to assess them.
| Material characteristic | Why it matters for performance | Characterization techniques |
| Material composition and aerogel type | Sets the broad performance envelope | SEM/EDS, EPMA, TXRF, ICP-MS/ICP-OES where relevant; FTIR, XPS, XRD, and Raman spectroscopy for chemistry or phase information |
| Density, porosity and pore structure | Governs weight, thermal conductivity, diffusion and access to internal surfaces | Gas pycnometry, gas adsorption porosimetry/BET, Micro-CT, microscopy |
| Surface chemistry and functionalization | Determines interaction with moisture, gases, liquids and reactive species | FTIR, XPS, water contact angle, TGA, and NMR where relevant |
| Form factor and mechanical integration | Influences handling, integration and service suitability | Microscopy, compression testing, tensile testing, DMA, TMA |
Table 2. Key aerogel features, performance impacts, and characterization approaches.
Because aerogel performance depends on multiple connected material characteristics, it usually cannot be explained by a single measurement. Covalent uses a multi-technique approach to connect composition, pore architecture, surface chemistry, thermal response, and final form with real-use performance.
In practice, this often starts with a set of characterization questions: What is the aerogel made of? How is the pore network structured? How does the surface interact with its environment? And how does the material respond to heat, handling, or service conditions?
Characterization questions researchers and engineers ask about aerogel samples
Characterization is most useful when techniques are chosen to answer a specific research, engineering, or performance question. For commercial or near-commercial aerogels, those questions may involve supplied material quality, product form, service exposure, installation damage, or batch-to-batch performance variation.
Table 3 connects common aerogel evaluation questions with characterization techniques that can help answer them.
| Characterization question | Relevant techniques | What the techniques can reveal |
| Has the network changed or collapsed? | Microscopy, SEM, FIB-SEM or Micro-CT where relevant | Morphology, cracking, collapse, coating quality, reinforcement distribution, or damage after processing, handling, installation, or exposure |
| Is the composition consistent? | EDS/EPMA; TXRF, ICP-MS, or ICP-OES where relevant | Local elemental variation by EDS/EPMA; bulk or trace composition and contamination by TXRF, ICP-MS, or ICP-OES |
| Did the surface treatment work? | FTIR, XPS, water contact angle | Surface chemistry, functional groups, wetting behavior, treatment effectiveness, and changes after moisture or environmental exposure |
| Has the chemistry changed? | FTIR, XPS, Raman spectroscopy, NMR, TGA | Bonding changes, degradation, oxidation, organic/inorganic chemistry, and mass-loss behavior |
| Is the structure amorphous or crystalline? | XRD, Raman spectroscopy | Crystallinity, phase changes, crystalline fillers, or structural changes after processing, heating or use conditions |
| Is the aerogel thermally stable? | TGA, TMA, DSC where relevant | Mass loss, decomposition, or oxidation by TGA; shrinkage, expansion, and dimensional stability by TMA; and thermal transitions by DSC where relevant |
| Is it mechanically robust enough? | Compression testing, tensile testing, DMA | Stiffness, strength, flexibility, damping, viscoelastic response, handling durability and suitability for product forms such as blankets, panels, films or composites |
| Why did performance vary? | SEM, EDS, FTIR/XPS, TGA, mechanical testing, and porosity testing where relevant | Whether differences are linked to morphology, composition, chemistry, thermal behavior, mechanical response, batch variation or service exposure. |
Table 3. Common aerogel characterization questions, relevant techniques, and what they can reveal.
In practice, these questions often overlap. A change in application performance may involve several factors at once, such as surface-treatment loss, pore-network damage, thermal degradation, composition variation, or mechanical weakening.
For that reason, aerogel characterization is usually strongest when the characterization plan is built around the specific performance issue being investigated, rather than treated as a fixed checklist of techniques.
Using characterization to assess aerogel application fit and performance variation
Characterization helps researchers and engineers evaluate application fit — whether an aerogel is suitable for its intended use — and performance variation: whether a specific sample has the structure, chemistry, stability, and durability needed to behave as expected.
This may mean comparing R&D samples, assessing differences between supplied materials, product forms, or batches, or investigating why performance changes after processing, handling, or service exposure.
Spec sheets and application trials can show whether an aerogel appears to meet requirements, but they do not always explain why performance varies between samples, batches, suppliers, or product forms. Characterization helps identify whether those differences are linked to composition, pore structure, surface chemistry, thermal response, or mechanical behavior.
Covalent’s materials scientists can help match characterization techniques to your specific application or performance question, so testing stays focused on what you need to understand.
Conclusion: Aerogel applications are best understood through characterization
Aerogels are often described as versatile materials because their chemistry, structure, and product form can be tailored for different uses. Some support thermal insulation and thermal barriers. Others use surface and interfacial properties to support adsorption, catalysis, and separation. Aerogels are also explored as functional materials and devices. Across these diverse areas, one thing remains consistent: performance depends on measurable material characteristics.
Characterization helps R&D teams understand not only what an aerogel is used for, but why a specific sample, commercial product form, or supplied material performs as expected — or why it does not. By linking application requirements with measured material evidence, characterization becomes central to assessing aerogel application fit, performance variation, and real-world suitability.