Hierarchical Adhesive Structure with Concave Threads
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Solution Overview
Problem
Existing methods for producing adhesive structures mimicking gecko toes lack the desired long-term adhesive strength due to inadequate modeling of the hierarchical structure of setae and spatulae.
Innovation Solution
A method involving a substrate with first and second threads, where both types of threads have concave lateral surfaces tapering to a flat head, is used to create a shaped body with enhanced adhesive properties, achieved through a process involving thermally conductive plates and solidifiable plastic, allowing for the formation of threads with specific dimensions and structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lithographic techniques and embossing processes are used to produce adhesive structures, then the hierarchical structure of setae and spatulae can be created, but the long-term adhesive strength is insufficient due to inadequate modeling of the hierarchical structure
Solution Approach 1:
The adhesive structure is segmented into two distinct hierarchical levels: first threads (setae) with lengths of 10-1000 μm and thickness of 1-100 μm, and second threads (spatulae) with lengths of 10-1000 μm and thickness of 0.1-10 μm. This segmentation creates a more accurate biological model that improves long-term adhesive strength by replicating the natural gecko toe structure.
Solution Approach 2:
The lateral surfaces of both first and second threads are designed with concave curvature, tapering from the underside toward the head. This curved geometry increases surface area and improves contact with substrates, enhancing adhesive performance while maintaining structural integrity over time.
2Ease of manufacture
If traditional adhesive structures are used, then the manufacturing process is simple, but the adhesive strength and surface adaptation are insufficient
Solution Approach 1:
The invention specifies precise dimensional parameters for the threads: first threads have lengths of 10-1000 μm and thickness of 1-100 μm, while second threads have lengths of 10-1000 μm and thickness of 0.1-10 μm. These parameter specifications enable consistent manufacturing of high-performance adhesive structures that balance complexity with producibility.
3Reliability
If the hierarchical structure is adequately modeled with first and second threads, then long-term adhesive strength is improved, but the device complexity increases
Solution Approach 1:
The two-thread hierarchical structure is integrated into a single solidified or hardened plastic body, where first and second threads are firmly connected at their bases. This merging approach maintains the complex hierarchical structure needed for strong adhesion while consolidating the structure into one piece, reducing assembly complexity.
Solution Approach 2:
The shaped body with hierarchical thread structure serves multiple functions: the first threads provide primary attachment to the substrate, while the second threads provide secondary attachment and enhance surface contact. This multi-functionality allows a single structure to achieve superior adhesive performance without requiring additional components.
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 method produces a shaped body with improved long-term adhesive strength and elasticity, allowing for better surface adaptation and increased adhesive performance compared to traditional structures.
Implementation Method 1
a layer of a solidifiable or curable plastic is introduced between two parallel, thermally conductive plates (tools) and pressure is then applied between the two plates. Then the two plates are heated in such a way that the layer heats up to a temperature above the glass transition point of the plastic used
Implementation Method 2
the two plates are heated in such a way that the layer heats up to a temperature above the glass transition point of the plastic used
Implementation Method 3
the toes of geckos consist of small, very fine hairs, the so-called setae, that adhere to any surface due to van der Waals forces
Data Source
Figure 1
Figure 2a~2d
Figure 3a~3b
AI summary
The invention relates to a moulded product comprising a substrate (1), to which a plurality of first fibres (10) is applied, the underside (11) of each fibre being permanently fixed to the surface (2) of the substrate (1), and a plurality of second fibres (20), the respective undersides (21) of which are permanently connected to the surfaces (12) of the first fibres (10). The flanks (15) of the first fibres (10) and the flanks (25) of the second fibres (20) are concave. The invention further relates to a method for producing a moulded product of this type and to the use of said product as the attachment surface of an object.