Liquid Crystal-Infused Porous Surfaces for Switchable Slipperiness

Solution Overview

Problem

Current slippery liquid-infused porous surfaces (SLIPS) rely on isotropic lubricants lacking long-range positional and orientational order, which limits their slipperiness and functionality, especially when interacting with water droplets, as they are prone to dewetting and fouling by oily contaminants.

Innovation Solution

Development of liquid crystal-infused porous surfaces that stabilize thermotropic liquid crystal mesogens against dewetting, allowing for mesogenic molecular order-dependent slipperiness and programmable cargo loading/release via external stimuli like heat and light, utilizing a porous polymer layer with an anisotropic lubricant that changes interfacial energy states based on liquid crystal phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If isotropic lubricants (silicone oils, fluorinated oils) are used to create SLIPS, then the surface achieves water-repellency and mobility, but the surface lacks long-range positional and orientational order and is prone to fouling by oily contaminants

Engineering Contradiction:

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent changes the molecular structure parameter of the lubricant from isotropic to anisotropic by using liquid crystals with mesogenic groups. This structural parameter change introduces long-range positional and orientational order, which prevents fouling by oily contaminants while maintaining droplet mobility through the ordered molecular arrangement that creates a more stable interface

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite lubricant system by combining liquid crystal molecules with specific mesogenic groups into the lubricant formulation. This composite approach integrates the water-repellent properties with the molecular ordering capabilities, achieving both mobility and resistance to fouling simultaneously

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If liquid crystal films are coated on conventional flat hydrophobic surfaces, then molecular order is introduced, but water droplet-induced dewetting occurs and droplets become pinned

Engineering Contradiction:

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent applies local quality by creating micro/nanostructured regions on the surface that provide anchoring sites for liquid crystal molecules. This localized structuring ensures proper orientation and stabilization of the liquid crystal film in specific areas, preventing dewetting while maintaining the anisotropic properties needed for droplet mobility

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses porous or micro/nanostructured surfaces as the substrate for liquid crystal coating. The porous structure provides increased surface area and anchoring points that stabilize the liquid crystal film against dewetting, while the controlled porosity allows the liquid crystal to form a continuous film that maintains droplet mobility

Inventive Principle:

Principle #31Porous materials

3Stability of the object's composition

If thermotropic liquid crystals with intrinsic positional and orientational order are used, then molecular order is achieved, but dewetting and pinning occur on conventional surfaces

Engineering Contradiction:

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies local quality by creating micro/nanostructured regions on the surface that provide anchoring sites for liquid crystal molecules. This localized structuring ensures proper orientation and stabilization of the liquid crystal film in specific areas, preventing dewetting while maintaining the anisotropic properties needed for droplet mobility

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses porous or micro/nanostructured surfaces as the substrate for liquid crystal coating. The porous structure provides increased surface area and anchoring points that stabilize the liquid crystal film against dewetting, while the controlled porosity allows the liquid crystal to form a continuous film that maintains droplet mobility

Inventive Principle:

Principle #31Porous 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 liquid crystal-infused surfaces exhibit switchable slipperiness between stick-slip and slippery modes, enabling efficient droplet transport and self-cleaning, with reversible cargo loading and release, enhancing their utility in smart surface reactors and water treatment applications.

Implementation Method 1

past studies have reported water droplet-induced dewetting of liquid crystal films coated on conventional flat hydrophobic surfaces

Methodology Applied

Scientific EffectDewetting:

Implementation Method 2

The liquid crystal-infused surfaces exhibit switchable slipperiness between stick-slip and slippery modes

Methodology Applied

Scientific EffectPhase transition: Phase Change

Implementation Method 3

the anisotropic lubricant infused within and over the porous polymer layer, such that the anisotropic lubricant at least partially fills the plurality of pores and forms a film on the surface

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS20240099985A1Liquid crystal-infused porous surfaces and methods of making and use thereof

Publication Date: 2024.03.28

AI summary

Disclosed herein are liquid crystal-infused porous surfaces and methods of making and use thereof.