Porous Polymer Surface Layer With Higher Shear Strength

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Solution Overview

Problem

Introducing porosity into polymer surfaces can weaken mechanical properties such as shear strength, limiting its application due to a loss in mechanical integrity.

Innovation Solution

A method for creating a porous surface on a polymer by heating it below its melting point and displacing a porogen layer to form a matrix layer, followed by leaching the porogen, resulting in a porous layer with increased shear strength that linearly increases with processing time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If porosity is introduced into polymer surfaces, then tissue integration and adhesion are improved, but shear strength and mechanical integrity are weakened

Engineering Contradiction:

Improvetissue integrationVSAvoidshear strength

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a porous surface layer only on the outer surface of the polymer device while maintaining the bulk material as dense and strong. This allows the surface to provide tissue integration benefits while the core material retains full mechanical strength. The porous layer is formed by selective degradation or removal of material from the surface, creating a gradient structure where porosity is concentrated where needed for biological interaction.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the polymer structure into distinct regions: a porous surface layer for tissue interaction and a dense core for mechanical support. This segmentation allows each region to be optimized independently - the porous surface promotes cell attachment and tissue growth while the dense interior maintains structural integrity and load-bearing capacity.

Inventive Principle:

Principle #1Segmentation

2Force

If porosity is introduced into polymer surfaces, then friction is increased, but mechanical properties are weakened

Engineering Contradiction:

ImprovefrictionVSAvoidmechanical properties

Core Design Contradiction:

ForceVSStrength

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If processing temperature is increased to create porous structure, then porosity is improved, but polymer degradation may occur

Engineering Contradiction:

ImproveporosityVSAvoidpolymer degradation

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by first incorporating a porogen (degradable material) into the polymer matrix during manufacturing, then subsequently degrading this porogen to create pores. This two-step approach allows the porous structure to be formed at low temperatures through controlled degradation of the porogen, avoiding the need for high-temperature processing that could degrade the polymer. The porogen acts as a sacrificial template that is removed after serving its structural purpose.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes phase transitions through the controlled degradation of the porogen material, which transitions from a solid incorporated phase to a removed phase, leaving behind porous spaces. This phase change approach enables pore formation through chemical or enzymatic degradation rather than thermal melting, avoiding polymer degradation while achieving the desired porous structure.

Inventive Principle:

Principle #36Phase transitions

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 process enhances the shear strength of the porous polymer surface while maintaining mechanical integrity, allowing for better tissue integration and adhesion in medical devices.

Implementation Method 1

heating a surface of a solid piece of polymer to a processing temperature below a melting point of the polymer

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

holding the processing temperature while displacing a porogen layer through the surface of the polymer to create a matrix layer

Methodology Applied

Scientific EffectPressure-driven displacement: Pressure Increase

Implementation Method 3

leaching the porogen, resulting in a porous layer with increased shear strength

Methodology Applied

Scientific EffectLeaching: Liquid-Liquid Extraction

Data Source

PatentUS20250381021A1Porous devices and methods of producing the same

Publication Date: 2025.12.18 NUVASIVE INC

AI summary

Devices and methods for making a polymer with a porous layer from a solid piece of polymer are disclosed. In various embodiments, the method includes heating a surface of a solid piece of polymer to a processing temperature and holding the processing temperature while displacing a porogen layer through the surface of the polymer to create a matrix layer of the solid polymer body comprising the polymer and the porogen layer. In at least one embodiment, the method also includes removing at least a portion of the layer of porogen from the matrix layer to create a porous layer of the solid piece of polymer.