Graphene Security Thread for Banknotes Using Liquid Crystal Color Shift
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Solution Overview
Problem
Existing security threads for banknotes lack robustness against counterfeiting, particularly due to the limitations of metallic coatings which can corrode and reduce electroconductivity, and the need for more advanced verifiable features.
Innovation Solution
The development of graphene nano-platelets based security threads, which incorporate liquid crystal (LC) for color-shifting effects, eliminate the use of metals to prevent corrosion and enhance electroconductivity, while also incorporating RFID antennas, barcodes, and trackable rare elements for multi-layered security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic coating is used in security thread, then security features are enhanced, but corrosion occurs and electroconductivity decreases
Solution Approach 1:
The patent changes the material parameter from metallic coating to graphene-based nanocomposite material. This parameter change eliminates corrosion while maintaining security features, as graphene is corrosion-resistant yet provides detectable magnetic and electrical properties for authentication.
Solution Approach 2:
The patent uses composite materials by combining graphene nanoplatelets with polymer matrices to create a nanocomposite security thread. This composite structure provides both the mechanical integrity needed for security threads and the unique electromagnetic properties for detection, while avoiding metal corrosion issues.
2Reliability
If metallic coating is used in security thread, then security features are enhanced, but electroconductivity decreases
Solution Approach 1:
The patent changes the material composition from metal to graphene-based nanocomposite, fundamentally altering the electrical properties. Graphene provides superior electroconductivity compared to metallic coatings, while its unique magnetic properties enable detection, thus improving both security features and electroconductivity simultaneously.
Solution Approach 2:
The patent substitutes metallic materials with graphene-based nanocomposites, replacing the traditional metallic system with a carbon-based nanomaterial system. This substitution maintains security functionality while improving electroconductivity and eliminating corrosion.
3Ease of manufacture
If single layer graphene protection is used, then manufacturing is simplified, but resistance against counterfeiting is insufficient
Solution Approach 1:
The patent segments the security thread into multiple functional layers: a polymer carrier film base layer, a graphene nanoplatelets ink coating layer providing security features, and optionally additional functional layers. This segmentation allows each layer to contribute specific properties, enhancing counterfeit resistance while maintaining manufacturing feasibility.
Solution Approach 2:
The patent creates a multi-layer composite structure combining polymer materials with graphene nanocomposites. This composite approach integrates the mechanical properties of polymers with the unique electromagnetic and mechanical properties of graphene, providing superior security against counterfeiting compared to single-layer structures.
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 graphene nano-platelets security threads provide enhanced resistance against counterfeiting through improved mechanical properties, adhesion, and electroconductivity, along with visible and covert security features that are detectable using specific readers, ensuring high-security banknotes.
Implementation Method 1
the graphene layer is heterogeneous and forms a pattern characterized by different levels of absorption of electromagnetic radiation, especially infrared radiation, visible light radiation or ultraviolet light passing through the pattern at its various points
Implementation Method 2
Special-effect inks printing using optically variable special-effect inks produces intriguing security elements that are quickly and easily identifiable and create irreproproducible effects. The special-effect inks change their appearance depending on the angle from which they are viewed
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
Graphene based security thread, methods of manufacturing the Same and application thereof. Currency notes comprises of graphene nano-platelets ink (2) based thin coated/printed film/indicia formed on the carrier film (1), graphene nano-platelets ink bands/pattern of variable sizes (21); or embed RFID antenna (5) made from graphene nano-platelets or graphene nano-platelets dots (7) on the substrate, when combined with LC based polymers (4) in form of an overlay will show distinct colour shift. Provided are also a UV curable lacquer/Graphene based lacquer (3) and a PET film (1A).