Long-Chain Entangled PDMS Gel Coating for Sustainable Self-Replenishment

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Solution Overview

Problem

Conventional slippery liquid-infused porous surfaces (SLIPS) suffer from lubricant depletion due to outward migration and shear-induced stress, leading to a loss of slippery function, while liquid-infused polymer surfaces (LIPS) face challenges in efficiently utilizing low-viscosity silicone oil for self-replenishment.

Innovation Solution

A coating method for long-chain entangled PDMS (LEP) gel is developed, involving impregnation with low-viscosity silicone oil, where long-chain free polymers are entangled in the PDMS network, enhancing sustainable self-replenishment through steps of mixing high-viscosity silicone oil, curing, and immersing in low-viscosity oil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional SLIPS is used with lubricant infused into micro- or nanoscale spaces, then slippery property is achieved, but lubricant depletion occurs due to outward migration and shear-induced stress

Engineering Contradiction:

Improveslippery propertyVSAvoidlubricant depletion

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The patent utilizes a porous substrate structure to infuse lubricant, creating SLIPS (Slippery Liquid-Infused Porous Surface). The porous structure allows lubricant to be stored within the substrate matrix, providing initial slippery properties. However, this approach suffers from lubricant depletion over time due to outward migration and shear stress, which the patent seeks to overcome by combining with self-replenishment mechanisms.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent implements self-replenishment mechanisms where the system automatically restores lubricant levels without external intervention. This includes using encapsulated lubricant reservoirs that release lubricant on-demand, or employing surface reactions that regenerate lubricant molecules. The self-service principle directly addresses lubricant depletion by enabling the surface to maintain its slippery property autonomously over extended periods.

Inventive Principle:

Principle #25Self-service

2Quantity of substance

If LIPS is used with lubricant diffused into polymeric network, then lubricant storage capacity is improved, but syneresis does not occur when oil content is below critical value

Engineering Contradiction:

Improvelubricant storage capacityVSAvoidself-replenishment function

Core Design Contradiction:

Quantity of substanceVSEase of operation

Solution Approach 1:

The patent employs parameter changes to control lubricant release behavior. By adjusting oil content above critical thresholds, modifying polymer crosslinking density, or changing environmental conditions (temperature, humidity), the system triggers syneresis - the spontaneous expulsion of lubricant from the polymer network. This allows the LIPS to transition from a stored-state to an active slippery-state on-demand, overcoming the limitation where low oil content prevents self-replenishment.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If low-viscosity silicone oil is used in LIPS, then slippery performance is enhanced, but efficient utilization and retention of lubricant becomes difficult

Engineering Contradiction:

Improveslippery performanceVSAvoidlubricant retention

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The patent creates composite material systems combining low-viscosity silicone oil with specifically designed polymer matrices or nanoscale confining structures. The composite structure provides both the low-friction benefits of low-viscosity lubricant and the retention capabilities through controlled porosity, surface energy matching, or nanoscale confinement effects. This composite approach enables simultaneous achievement of enhanced slippery performance and improved lubricant retention.

Inventive Principle:

Principle #40Composite materials

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 LEP gel achieves excellent slippery, anti-fouling, and anti-icing performance by maintaining a lubricating layer through sustainable self-replenishment, with improved lubricant retention and reduced bacterial adhesion.

Implementation Method 1

a liquid-infused polymer surface (LIPS) is fabricated by diffusing lubricant molecules into the polymeric network of a polymer

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

The syneresis occurs when the amount of oil absorbed by the LIPS is over a predetermined critical value

Methodology Applied

Scientific EffectSyneresis:

Data Source

PatentUS20250250461A1Coating method of long-chain entangled PDMS gel with sustainable self-replenishment of lubricating layer

Publication Date: 2025.08.07 POSTECH ACADEMY INDUSTRY FOUNDATION

AI summary

The present disclosure is related to a coating method of a long-chain entangled PDMS (LEP) gel in which self-replenishment of a lubricating layer is sustainable. More specifically, it is possible to achieve excellent slippery properties, anti-fouling performance, and anti-icing performance for a long period of time due to sustainable self-replenishment performance of a surface coated with LEP gel, by forming LEP gel impregnated with a low-viscosity silicone oil as a lubricant into the surface of long-chain entangled PDMS (LEP), in which long-chain free polymers are entangled in PDMS networks.