Microstructured Surface Peak Valley Geometry for Cleanability
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Solution Overview
Problem
Microstructured surfaces, while effective in reducing biofilm formation, can be difficult to clean due to the size of bristles or fibers being larger than the spacing between microstructures, making them less effective for non-medical articles.
Innovation Solution
A microstructured surface with peak structures and adjacent valleys, where the valleys have a maximum width ranging from 10 microns to 250 microns and side wall angles greater than 10 degrees, is used, which can be applied to various articles using methods like microreplication techniques, providing a pressure-sensitive adhesive for bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a microstructured surface with small spacing between microstructures is used, then biofilm formation is reduced, but cleaning becomes difficult because bristles or fibers are larger than the space between microstructures
Solution Approach 1:
The patent changes the geometric parameters of the microstructures, specifically increasing the spacing between microstructures to dimensions larger than cleaning bristles or fibers (e.g., valleys with maximum width from 10 microns to 250 microns). This parameter modification allows cleaning tools to access and effectively remove contaminants while the microstructured surface still provides biofilm resistance through its engineered roughness index of 5 to 20.
2Ease of operation
If a smooth surface is used, then cleaning is easy, but microorganism removal and touch transfer reduction are less effective compared to microstructured surfaces
Solution Approach 1:
The patent applies local quality by creating a microstructured surface with specific geometric features (peaks and valleys with controlled dimensions and engineered roughness index of 5 to 20) that provide enhanced microorganism removal and touch transfer reduction properties in specific locations, while maintaining overall surface functionality for cleaning applications.
3Reliability
If microstructures with steep side wall angles are used, then microorganism removal is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a side wall angle range (greater than 10 degrees, with facets forming apex angles typically ranging from about 20 to 120 degrees) that balances microorganism removal effectiveness with manufacturability. This parameter optimization allows standard manufacturing processes to produce the microstructures while achieving the desired performance characteristics for contaminant removal.
Data Source
AI summary
Films and articles are described comprising a microstructured surface having an array of peak structures and adjacent valleys. For improved cleanability, the valleys preferably have a maximum width ranging from 10 microns to 250 microns and the peak structures have a side wall angle greater than 10 degrees. The peak structures may comprise two or more facets such as in the case of a linear array of prisms or an array of cube-corners elements. The facets form continuous or semi-continuous surfaces in the same direction. The valleys typically lack intersecting walls. Also described are methods of making and methods of use. The microstructured surface of the article can be prepared by various microreplication techniques such as coating, injection molding, embossing, laser etching, extrusion, casting and curing a polymerizable resin; and bonding microstructured film to a surface or article with an adhesive.