Liquid-Impregnated Surfaces Resist Impalement and Frost
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Solution Overview
Problem
Existing non-wetting surfaces, such as superhydrophobic and superoleophobic surfaces, are susceptible to impalement and lose their non-wetting capabilities due to impinging liquids, and they become ineffective against frost and ice formation, requiring costly and time-consuming active methods for de-icing, while passive methods using sacrificial liquids pose environmental risks.
Innovation Solution
Engineering liquid-impregnated surfaces with micro/nano-engineered features that resist impalement and frost formation by stabilizing an impregnating liquid within the surface matrix, ensuring non-wettability without the need for continuous replenishment, using specific impregnating liquids and surface geometries to maintain coverage and prevent cloaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas (air) is entrained within surface textures to create non-wetting surfaces, then water repellency and reduced adhesion are achieved, but the surfaces become susceptible to impalement and lose non-wetting capabilities
Solution Approach 1:
The patent changes the phase parameter of the impregnating medium from gas (air) to liquid, creating liquid-impregnated surfaces that maintain non-wetting properties while being resistant to impalement. This parameter change transforms the surface from vulnerable to robust without sacrificing non-wetting functionality.
2Object-affected harmful factors
If sacrificial liquids are applied to prevent frost and ice formation, then ice adhesion is reduced, but environmental problems arise from leakage
Solution Approach 1:
The patent changes the physical state parameter from liquid to solid by using solid particles instead of sacrificial liquids. This transformation maintains the anti-icing function while eliminating the environmental harm caused by liquid leakage, as solid particles do not spread or contaminate the environment.
Solution Approach 2:
The patent uses solid particles that replicate the protective function of sacrificial liquids without their harmful side effects. The solid particles create a similar protective interface against ice formation but remain contained and environmentally benign.
3Reliability
If micro/nano surface textures are used to create superhydrophobic surfaces, then water contact is resisted, but the surfaces require continuous replenishment of impregnating liquid
Solution Approach 1:
The patent creates surfaces that self-maintain their impregnating layer through capillary forces and surface energy effects. The solid particles automatically redistribute and replenish themselves without external intervention, eliminating the need for continuous manual maintenance while preserving water repellency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The liquid-impregnated surfaces provide robust non-wetting properties, resisting impalement and frost formation, with reduced ice adhesion and improved roll-off angles, eliminating the need for continuous fluid replenishment and minimizing environmental impact.
Implementation Method 1
a liquid filling pores or other tiny wells on the surface
Implementation Method 2
an air-water interface within the micro/nano surface textures
Implementation Method 3
Hydrophobic surfaces have a high energy barrier for ice nucleation and low ice adhesion strength
Implementation Method 4
micro/nano surface textures has provided nonwetting surfaces capable of achieving less viscous drag, reduced adhesion to ice and other materials
Data Source
AI summary
In certain embodiments, the invention is directed to apparatus comprising a liquid-impregnated surface, said surface comprising an impregnating liquid and a matrix of solid features spaced sufficiently close to stably contain the impregnating liquid therebetween or therewithin, and methods thereof. In some embodiments, one or both of the following holds: (i) 0<ϕ≤0.25, where ϕ is a representative fraction of the projected surface area of the liquid-impregnated surface corresponding to non-submerged solid at equilibrium; and (ii) Sow(a)<0, where Sow(a) is spreading coefficient, defined as γwa−γwo−γoa, where γ is the interfacial tension between the two phases designated by subscripts w, a, and o, where w is water, a is air, and o is the impregnating liquid.