Cellulose Hydrogel Strength and Transparency via Parameter Changes
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Solution Overview
Problem
Existing cellulose hydrogels often compromise on properties like strength, transparency, water content, and biocompatibility, making them unsuitable for various applications, including ophthalmic materials like contact lenses.
Innovation Solution
Development of cellulose hydrogels with specific properties such as high water content, high transparency, high permeability, high biocompatibility, high tensile strength, and optimal thickness, achieved through a process involving activation of cellulose with a solvent, optional removal and rehydration steps, and incorporation of polymers like HEMA or PHEMA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If attempts are made to optimize certain physical properties of hydrogels, such as strength, then tensile strength is improved, but transparency or water content deteriorates
Solution Approach 1:
The patent applies parameter changes by systematically varying the cellulose concentration (from 2% to 65% by weight) and water content ratios to achieve the optimal balance between tensile strength and transparency. Specifically, the patent discovers that a cellulose concentration of 40-65% by weight provides both high tensile strength (1000-5000 kPa) and high transparency (>85% at 550 nm), resolving the traditional trade-off between these properties.
2Strength
If attempts are made to optimize certain physical properties of hydrogels, such as strength, then tensile strength is improved, but water content deteriorates
Solution Approach 1:
The patent resolves this contradiction by changing the parameter of cellulose concentration to 40-65% by weight, which simultaneously achieves high tensile strength (1000-5000 kPa) and high water content (50-90% by weight). This parameter optimization allows the hydrogel to maintain both mechanical strength and high water content, which is critical for ophthalmic applications.
3Strength
If cellulose concentration is increased to improve tensile strength, then strength is improved, but transparency may deteriorate
Solution Approach 1:
The patent identifies a specific parameter range for cellulose concentration (40-65% by weight) where both tensile strength and transparency are optimized. Within this range, the hydrogel achieves tensile strength of 1000-5000 kPa while maintaining transparency exceeding 85% at 550 nm, thus resolving the trade-off between strength and transparency.
4Strength
If cellulose concentration is increased to improve tensile strength, then strength is improved, but water content may deteriorate
Solution Approach 1:
The patent optimizes the cellulose concentration parameter to 40-65% by weight, which enables the hydrogel to simultaneously achieve high tensile strength (1000-5000 kPa) and high water content (50-90% by weight). This parameter optimization resolves the contradiction between strength and water content, making the hydrogel suitable for ophthalmic applications where both properties are critical.
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 resulting cellulose hydrogels exhibit enhanced tensile strength, transparency, and biocompatibility, making them suitable for diverse applications including contact lenses and wound dressings, while maintaining high water content and permeability.
Implementation Method 1
contacting cellulose with a solvent to activate the cellulose
Implementation Method 2
allowing the solution of (iii) to gel
Implementation Method 3
hydrogels are water-insoluble polymers having the ability to swell in water or aqueous solution without dissolution and to retain a significant portion of water or aqueous solution within their structure
Data Source
AI summary
The present invention provides cellulose hydrogels having one or more of the following properties: high water content, high transparency, high permeability, high biocompatibility, high tensile strength and an optimal thickness. The present invention further provides a process for preparing a cellulose hydrogel comprising: (i) contacting cellulose with a solvent to activate the cellulose; (ii) optionally removing the solvent from the activated cellulose; (iii) substantially dissolving the activated cellulose to form a solution; (iv) allowing the solution to gel; and optionally (v) drying the gel and rehydrating the gel. The cellulose hydrogel can have many uses, including uses as contact lenses.