Mold Surface Structuring via Laser and Anodic Oxidation
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Solution Overview
Problem
Existing mold technologies are unable to produce surface structures smaller than 1 μm or 100 nm, limiting the creation of microstructured and nanostructured plastic components with enhanced surface areas for applications such as cell colonization and pharmaceutical delivery.
Innovation Solution
A two-stage method for producing molds with first structural elements via laser structuring or machining, followed by second structural elements through anodic oxidation, resulting in a significant increase in surface area by combining microstructuring and nanostructuring, with the latter having a smaller lateral extent and depth than the former.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional single-stage laser structuring or machining is used, then manufacturing process is simple, but surface structures smaller than 1 μm or 100 nm cannot be produced
Solution Approach 1:
The manufacturing process is divided into two sequential stages: first, macroscopic structural elements are created using laser structuring or machining; second, microscopic structural elements are formed through anodic oxidation. This segmentation enables production of structures at both >1 μm and <100 nm scales that cannot be achieved by a single method.
Solution Approach 2:
The first structural elements are pre-formed on the mold surface before the second structural elements are added. The pre-formed macroscopic structures serve as a foundation that guides and supports the subsequent formation of microscopic structures through anodic oxidation, enabling hierarchical structuring.
2Area of moving object
If only macroscopic structures are produced, then manufacturing is easier, but effective surface area is insufficient for applications requiring high surface area
Solution Approach 1:
Anodic oxidation creates a porous oxide layer on the mold surface, forming microscopic structural elements with high surface area to volume ratio. This porous microstructure dramatically increases the effective surface area available for plastic film contact, enabling applications requiring high surface area such as cell colonization and pharmaceutical delivery.
Solution Approach 2:
Microscopic structural elements are nested upon the macroscopic structural elements, creating a hierarchical surface topology. The microstructures cover and extend from the macroscopic features, combining both scales to achieve cumulative surface area multiplication (10-500 times greater than macroscopic dimensions alone).
3Area of moving object
If two-stage structuring process is used, then surface area is significantly increased, but manufacturing process becomes more complex
Solution Approach 1:
The second stage replaces mechanical machining with electrochemical anodic oxidation to create microscopic structures. This substitution enables formation of sub-100 nm features that are difficult to achieve mechanically, while the electrochemical process naturally produces the desired porous microstructure without requiring complex mechanical tooling.
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 enables the creation of plastic components with an enlarged effective surface area, improving biocompatibility and enabling the delayed release of active pharmaceutical ingredients, while maintaining the structural integrity and functionality of the components.
Implementation Method 1
the laser structuring can be carried out with short-pulse lasers having a pulse duration of less than 100 nanoseconds, less than 25 nanoseconds, or less than 100 femtoseconds. Such short-pulse lasers cause material ablation through nonlinear optical and thermal effects
Implementation Method 2
Such short-pulse lasers cause material ablation through nonlinear optical and thermal effects
Implementation Method 3
Such short-pulse lasers cause material ablation through nonlinear optical and thermal effects
Implementation Method 4
In a further process step, second structural elements are produced which have a smaller lateral extent and/or a smaller depth than the first structural elements. In some embodiments of the invention, the second structural elements are produced by anodic oxidation. In an anodic oxidation, the mold is connected as the anode and immersed in an acidic electrolyte, so that an oxide layer forms on the surface of the anode.
Implementation Method 5
In an anodic oxidation, the mold is connected as the anode and immersed in an acidic electrolyte, so that an oxide layer forms on the surface of the anode.
Data Source
Figure 1a~3b
Figure 4a~6b
Figure 7a~9
AI summary
The invention relates to a method for creating a surface structure (1) on a mold (2), wherein first structural elements (11) are created using a laser structuring process in a first step, and second structural elements (12), which are smaller than the first structural elements (11), are created using an anodic oxidation process in another step following the laser structuring process. The invention further relates to a mold of said type and finally to a plastic film or a plastic component having a surface structure as well as to a method for the production thereof.