Electrospun Nonwoven Composition for Thermal Stability in Implants
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrospun materials face issues such as instability due to amorphous nature and highly elongated polymer chains, leading to crystallization, shrinkage, and loss of desirable mechanical and chemical properties, particularly at body temperature, which affects their performance in medical devices.
Innovation Solution
Development of electrospun materials comprising two fiber populations, one with a block semi-crystalline copolymer and the other with a polyester or polyester carbonate, achieving characteristics like softness, low residual solvent content, and mechanical strength, with specific glass transition temperatures and tensile modulus, and optionally incorporating bioactive agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrospun materials are produced using rapid whipping instability to achieve high elongation ratio and small fiber diameters, then fiber formation occurs rapidly with enhanced surface area to volume ratio, but polymer chains remain highly elongated and amorphous leading to thermal instability and crystallization at body temperature
Solution Approach 1:
The patent applies parameter changes by controlling the glass transition temperature (Tg) of the polymer to be above body temperature (37°C). This parameter change ensures that the polymer chains remain in a glassy, stable state at physiological temperatures, preventing the thermal instability and crystallization that would otherwise occur after rapid electrospinning-induced elongation.
Solution Approach 2:
The patent employs composite materials by combining polymers with specific glass transition temperatures above 37°C with other materials to create electrospun constructs that maintain both the desired fibrous morphology from rapid electrospinning and thermal stability at body temperature, resolving the contradiction between rapid fiber formation and thermal stability.
2Stress or pressure
If electrospun materials undergo thermal treatment or exposure to body temperature, then stress relief and cold crystallization may occur, but this distorts fiber topography, shrinks pore size, and alters mechanical properties
Solution Approach 1:
The patent applies preliminary anti-action by selecting polymers whose glass transition temperature is above body temperature, which prevents stress relief and crystallization from occurring at physiological temperatures. This preliminary selection of material properties counteracts the potential harmful effects of thermal exposure before they can manifest.
Solution Approach 2:
By changing the glass transition temperature parameter of the polymer to be above 37°C, the patent ensures that the material remains dimensionally stable and maintains its fiber topography and pore structure at body temperature, preventing the distortion and shrinkage that would otherwise occur during thermal exposure or physiological use.
3Area of stationary object
If highly elongated polymer chains are confined within micron-sized fibers through rapid electrospinning, then fiber formation is achieved with enhanced surface area, but the amorphous nature leads to morphological and mechanical property changes when exposed to heat
Solution Approach 1:
The patent changes the glass transition temperature parameter of the polymer to be above body temperature, which stabilizes the highly elongated polymer chains within the micron-sized fibers. This parameter change prevents the amorphous regions from undergoing crystallization or relaxation at physiological temperatures, thereby maintaining mechanical property stability while preserving the high surface area to volume ratio.
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 materials exhibit improved mechanical performance, thermal stability, and enhanced cell infiltration and migration, overcoming traditional trade-offs of residual solvent content and structural integrity, suitable for medical device applications.
Implementation Method 1
the electrospinning method, using an electrical charge to draw very fine, typically on the micro or nano scale, fibers from a liquid
Implementation Method 2
By applying a critical voltage to overcome the surface tension of the polymer solution (and with sufficient molecular chain entanglement in solution) fiber formation can occur
Implementation Method 3
fiber formation occurs on the order of milliseconds due to the rapid evaporation of the solvent, inhibiting polymer crystallization
Implementation Method 4
This high elongation ratio is driven by the electric force induced whipping instability
Data Source
AI summary
Disclosed herein are nonwoven materials, such as electrospun materials, that have one or more of the characteristics of softness, loftiness, particular pore sizes, little to no solvent retention, and mechanical and dimensional stability for use in implanted medical devices.