Patterned Metal Medical Balloons With Heat-Sinking PVD
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for applying metal layers on catheter balloons, such as electroless plating, adhesive backed metallic foils, and nano-particle inks, suffer from issues like adhesion failures, thickness constraints, and thermal degradation of the polymer substrate, making them unsuitable for medical applications.
Innovation Solution
A method involving PVD deposition of metallic patterns on thin-walled polymer balloons using a stencil mask that actively pulls heat away from the balloon during the process, minimizing thermal degradation and ensuring adhesion, while using specific process parameters and materials to maintain the balloon's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electroless plating is used to apply metal layer on balloon catheter, then metal coating can be applied to polymer surface, but toxic chromic acid-based chemical etching process is required which is not acceptable for medical industry applications
Solution Approach 1:
The patent replaces the chemical etching process with a physical vapor deposition process. Instead of using toxic chromic acid-based chemical solutions to prepare the polymer surface, the invention uses PVD to directly deposit metal atoms onto the polymer surface in a vacuum environment, eliminating the need for harmful chemical etching while achieving suitable metal coating adhesion for medical applications
2Ease of manufacture
If adhesive backed metallic foil is used to provide metal layer on polymer, then metal coating can be applied without chemical etching, but bonding strength is insufficient for medical industry applications
Solution Approach 1:
The patent replaces the adhesive bonding mechanism with direct physical vapor deposition. Instead of relying on adhesive layers to bond metal foil to the polymer, the invention uses PVD to deposit metal atoms that directly adhere to the polymer surface through physical vapor deposition, achieving superior bonding strength suitable for medical devices while maintaining ease of manufacture without chemical etching
3Ease of manufacture
If adhesive backed metallic foil is used to provide metal layer on polymer, then metal coating can be applied, but too much thickness is added to the polymer substrate
Solution Approach 1:
The patent replaces the adhesive foil approach with thin-film physical vapor deposition. Instead of using adhesive-backed metallic foil that adds significant thickness, the invention uses PVD to deposit ultra-thin metal films directly onto the polymer surface, achieving the required metal coating functionality with minimal added thickness that preserves the flexibility and performance characteristics of the underlying polymer substrate
4Length of stationary object
If metallic filled paint is used to make polymer substrate conductive for electroplating, then thinner metal layer can be achieved, but adhesion fails due to paint layer weakness
Solution Approach 1:
The patent replaces the paint-based approach with direct physical vapor deposition. Instead of using metallic filled paint that creates a weak adhesion layer, the invention uses PVD to deposit metal atoms that directly bond to the polymer surface, achieving both thin metal layer thickness and strong adhesion simultaneously, eliminating the adhesion failures associated with paint-based methods
5Length of stationary object
If nano-particle conductive ink is CNC printed on polymer substrate, then thin metal layer can be achieved, but thermal degradation occurs due to high sintering temperatures
Solution Approach 1:
The patent replaces the thermal sintering process with physical vapor deposition at low temperatures. Instead of using nano-particle conductive ink that requires high-temperature sintering to achieve electrical conductivity and adhesion, the invention uses PVD to deposit metal atoms that bond to the polymer surface at much lower temperatures, preventing thermal degradation of the polymer substrate while achieving the required thin metal layer thickness and electrical conductivity
6Length of stationary object
If PVD process is used to deposit metallic films on thin walled polymer structures, then thin metal coating can be applied, but high temperatures cause melting or thermal deformation of polymer substrate
Solution Approach 1:
The patent introduces a cooling system as an intermediary element during the PVD process. Instead of allowing the polymer substrate to reach high temperatures that cause melting or thermal deformation, the invention incorporates cooling mechanisms that actively remove heat from the substrate during metal deposition, enabling thin metal coating application while maintaining polymer integrity and preventing thermal damage
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 allows for the deposition of metal patterns on catheter balloons without deforming or degrading the polymer material, ensuring flexibility and stability, thus addressing the limitations of existing methods.
Implementation Method 1
A different approach to these methods involves Physical Vapor Deposition ('PVD'), also sometimes called Chemical Vapor Deposition, or sputtering. PVD has sometimes been used to deposit metallic films on thin walled polymer structures used in medical devices and procedures
Implementation Method 2
Sputtering is a well-developed technology for depositing thin coatings of one material (the deposited layer, or deposition layer) on another material (the substrate)
Implementation Method 3
The sputtering process requires the production of a plasma by a plasma power source which electrically induces ionization of the inert carrier gas from the residual inert gas in the vacuum chamber
Implementation Method 4
The PVD process starts in a vacuum chamber under high vacuum (typically on the order of 0.1 millitorr) to prevent unwanted oxidation or other reactions
Implementation Method 5
By using a system design which actively pulls heat away from the balloon during the PVD process and by using proper process parameters, the patterned metal layer is deposited on the balloon through a stencil mask without deforming or degrading the polymer material of the balloon
Data Source
AI summary
A thin walled balloon formed in polymer tubing has a patterned metal layer on its outer surface, created by physical vapor deposition (PVD). The pattern is defined by a stencil mask assembled around the balloon, with the balloon inflated therein. The PVD occurs without deforming or degrading the polymer material of the balloon, by actively pulling heat away from the balloon a) by forming the stencil mask out of metal; b) by providing a metal heat conduction path away from the balloon to a heat sink, such as outside the vacuum chamber, and/or c) by flow of a cooling fluid within the balloon during the PVD process. Proper PVD process parameters are selected to minimize heat generation, such as having argon pressure in the range of 0.8 to 1.2 milli-torr and generating the plasma at a power of less than about 200 watts/square inch of effective target surface area.