The reason aerogels can achieve "ultra-thin yet highly efficient thermal insulation" is not due to material thickness, but rather to their unique nanoscale microstructure and comprehensive suppression of all three modes of heat transfer.

I. Why can aerogels achieve ultra-thin thermal insulation? Key conclusions first:

In short:

Through its nanoporous structure, aerogels fundamentally block heat conduction, convection, and radiation, achieving extremely low thermal conductivity even at very thin thicknesses.

This is the fundamental reason why aerogels are considered "one of the solid materials with the lowest thermal conductivity currently available."

II. The Microstructure of Aerogels Determines Their Ultrathin Insulation Capability

1. Nanoscale Pore Structure is the Key Foundation

The internal structure of aerogels has the following typical characteristics:

Pore Size: Approximately 10–100 nm (nanometer scale)

Porosity: Typically ≥90%

Extremely fine, continuous, but not dense solid framework

The interior is filled with stationary gas (usually air)

This structure is completely different from traditional fibrous or closed-cell materials and is a prerequisite for "ultrathin insulation."

III. The Three Major Physical Principles of Aerogel Ultrathin Insulation

1. Reduced Limits in Heat Conduction (Core Reason)

In ordinary materials, heat is mainly transferred through solid conduction and gas conduction.

However, in aerogels:

The solid framework is extremely fine with very few contact points.

The heat transfer path in the solid is significantly lengthened.

The contribution of solid thermal conductivity is reduced to an extremely low level.

Simultaneously, the gas is confined within the nanopores, forming the so-called "Knudsen effect."

When the pore size is smaller than the mean free path of gas molecules, gas molecules cannot effectively transfer heat.

This directly leads to:

A significant decrease in gas thermal conductivity

A total thermal conductivity far lower than that of traditional materials

Therefore, even with a very thin layer, aerogel still possesses extremely strong thermal insulation capabilities.

2. Structurally "Eliminating" Air Convection

Air convection requires two conditions:

1. Sufficiently large space

2. Air can flow freely

However, the nanoporous structure of aerogel:

Individual pores are extremely small

Air is completely "locked in"

No effective convection path can be formed

This means:

Aerogel directly eliminates the possibility of convective heat transfer at the structural level.

This is also an important reason why it maintains stable thermal insulation performance even in an ultra-thin state.

3. Effective Suppression of Thermal Radiation

In medium- and high-temperature environments, the proportion of thermal radiation increases significantly.

Aerogels reduce radiative heat transfer in the following ways:

The porous structure causes multiple scattering of thermal radiation.

The nanoframework blocks infrared radiation.

Radiative heat transfer can be further reduced by adding light-blocking agents.

Therefore, even when the material is very thin, radiative heat cannot directly penetrate the aerogel layer.

IV. Why are traditional insulation materials difficult to achieve "ultra-thin" thickness?

From a principle comparison:

| Material Type | Insulation Method | Thickness Dependence |

| Glass Wool / Rock Wool | Fiber + Air | High |

| Rubber & Plastic | Closed-Cell Gas | Medium |

| Polyurethane | Foamed Structure | Medium |

| Aerogel | Nanopores Block Heat Transfer | Extremely Low |

Traditional materials require "sufficient thickness" to extend the thermal path;

While aerogels directly reduce heat transfer efficiency at the microscale, the thickness requirement is significantly reduced.

V. Ultra-thin insulation does not equal "arbitrarily thinner"

It needs to be objectively stated that:

Aerogel's "ultra-thin" is relative to traditional materials.

In actual engineering, a reasonable thickness still needs to be calculated based on the working conditions.

The greater the temperature difference and the more complex the environment, the more appropriate the thickness needs to be.

For this reason, aerogel is usually used in:

Space-constrained areas

High-performance energy-saving systems

High-value-added or special working condition projects

VI. Engineering significance of the advantages of ultra-thin aerogel insulation

From an application perspective, ultra-thin aerogel insulation brings:

Saving installation space

Reducing system load

Increasing the design freedom of equipment and buildings

Solving the problem of "thickness limitations" of traditional materials

This is also the reason for its gradual promotion in the fields of industry, construction, and energy.

The essence of aerogel's ability to achieve ultra-thin insulation lies in its nanoscale porous structure, which simultaneously inhibits heat conduction, convection, and radiation at the physical level. This "structural insulation" mode enables it to maintain excellent thermal insulation performance even with a very small thickness, which is something that traditional materials cannot achieve by simply reducing their thickness.