Liquid nanofoam cushioning system for enhanced performance and comfort

Overview

Liquid nanofoam (LN) is an advanced, reusable energy mitigation material system composed of nanoporous particles, a non-wettable liquid, and gas. Unlike conventional solid foam liners used in athletic and military helmets, LN delivers approximately ten times the energy absorption efficiency while being fully self-recoverable after repeated impacts. This breakthrough enables the design of significantly thinner cushioning structures without added weight, opening new possibilities for personalized sports footwear with superior impact protection, breathability, and comfort.

Technical specifications

• Composition: Nanoporous particles combined with non-wettable liquid and gas, forming a fluid-like material that flows into and out of nanopores under pressure.

• Working mechanism: Under external pressure, liquid and gas are forced into nanopores, absorbing kinetic energy. When pressure is removed, they flow back out spontaneously, enabling full repeatability.

• Manufacturing: LN pouches are produced via radio-frequency welding, achieving sealing strength above 20 MPa to ensure structural integrity during sports use.

• Impact performance: A 0.25-inch thick LN pouch reduces peak acceleration under blunt impact by 25%–33% compared to 0.75-inch thick EPS foam (military helmets) and 0.75-inch thick TPU foam (top-rated football helmets), respectively, while reducing thickness by 67% with no weight increase.

• Reusability: LN maintains identical energy mitigation performance on consecutive impacts, whereas EPS and TPU foams degrade by 78% and 36%, respectively.

• Tunability: Working pressure can be precisely adjusted between 0.3 MPa and 30 MPa, enabling full personalization for different body weights and sport requirements.

• Structural integration: The fluid-like nature of LN allows integration into complex 3D hollow structures manufactured through additive manufacturing, enhancing both mechanical cushioning and airflow for thermal comfort.

Technology readiness level

The technology has been experimentally validated through laboratory impact testing, demonstrating superior energy absorption and reusability compared to commercial foam liners. LN pouches have been manufactured and mechanically characterized. Future work includes tuning working pressure for personalized applications, designing advanced hollow structures for improved airflow via additive manufacturing, quantifying heat flow under repeated mechanical loading, and developing sport-specific cushioning designs for basketball, football, running, and walking. The technology is at an early-to-mid stage of development, ready for collaborative refinement toward commercial sports footwear applications.