Polymer Water-Repellent Surface via Solvent-Induced Crystallization
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Solution Overview
Problem
Existing methods for creating highly hydrophobic and water-repellent surfaces require materials like silicon compounds and titanium oxide nanoparticles, which are costly and complex, and do not efficiently produce surfaces with high hydrophobicity and water repellency.
Innovation Solution
A method involving contacting a crystalline or semicrystalline polymer with a solvent where the solubility parameter difference is less than 7.5 MPa1/2, and the solvent's boiling point is higher than the polymer's crystallization temperature, followed by controlled drying, forms a highly hydrophobic and water-repellent surface without additional materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods using silicon compounds or titanium oxide nanoparticles are employed to create water-repellent surfaces, then high hydrophobicity and water repellency are achieved, but manufacturing complexity and material cost increase
Solution Approach 1:
The patent extracts and removes the skin layer formed during solvent treatment, which contains the fine crystalline structure responsible for water repellency. This allows the base polymer material to be simplified while maintaining the hydrophobic surface properties through the extracted skin layer structure.
Solution Approach 2:
The patent changes the physical and chemical parameters of the polymer by controlling solvent selection (based on solubility parameters), treatment temperature, and drying conditions. These parameter changes induce spontaneous crystallization and skin layer formation without requiring additional nanoparticles or complex coatings.
2Reliability
If additional materials like silicon compounds and titanium oxide nanoparticles are used to enhance water repellency, then surface hydrophobicity improves, but material cost increases
Solution Approach 1:
The patent enables the polymer material to self-organize and self-structure through controlled solvent treatment and drying. The polymer spontaneously forms a skin layer with fine crystalline structures that provide water repellency, eliminating the need for expensive external nanoparticles or additives.
Solution Approach 2:
The patent uses a homogeneous polymer-solvent system where the solvent interacts with the polymer to induce uniform crystallization and skin layer formation. This homogeneous approach replaces heterogeneous mixtures of polymer plus nanoparticles, reducing material complexity and cost.
3Reliability
If complex multi-step processes are used to create fine surface structures, then water repellency improves, but manufacturing time and process complexity increase
Solution Approach 1:
The patent performs preliminary solvent treatment and controlled drying to pre-form the skin layer with fine crystalline structure before final product completion. This preliminary action creates the water-repellent surface in advance, eliminating the need for subsequent complex surface modification steps.
Solution Approach 2:
The patent utilizes phase transitions of the solvent (evaporation) and the polymer (crystallization) to spontaneously form the fine surface structure. By controlling temperature and humidity during drying, the polymer transitions from a solvent-swollen state to a crystalline skin layer, creating water repellency through natural phase changes rather than mechanical processing.
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
This method allows for the creation of a highly hydrophobic and water-repellent surface in a simple and cost-effective manner, achieving excellent hydrophobicity and water repellency with a removable skin layer.
Implementation Method 1
contacting a member made of a crystalline or semicrystalline polymer with a solvent... a difference between Hildebrand's solubility parameters of the polymer and the solvent is less than 7.5 MPa1/2
Implementation Method 2
a skin layer is formed on a surface of the member... both surfaces of a processed body surface contacting with the skin layer and a skin layer surface contacting with the processed body surface are surfaces having high hydrophobicity and water repellency
Implementation Method 3
taking the member contacted with the solvent out of the solvent-contacting region and drying the member... a boiling point of the solvent is higher than a crystallization temperature (Tc) of the polymer
Implementation Method 4
a crystalline or semicrystalline polymer... a temperature of the solvent when the member is contacted with the solvent is Tc of the polymer±50° C.... a temperature of drying the member is lower than Tc of the polymer by at least 20° C.
Data Source
AI summary
A method of manufacturing a processed body having a hydrophobic and water-repellent surface, and a processed body having a hydrophobic and water-repellent surface. The method includes: a step of contacting a member made of a crystalline or semicrystalline polymer with a solvent in a solvent-contacting region; and a step of taking the member contacted with the solvent out of the solvent-contacting region and drying the member.