Porous Polyethylene Sorbent with Swellable Pockets for Oil Recovery
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Solution Overview
Problem
Existing oil sorbent films have limited oil uptake capacity due to their thickness and are energy-intensive and costly to produce, while also being inefficient in removing thin water-borne oil films and occupying excessive space.
Innovation Solution
A method for preparing freestanding porous polyethylene thin films with swellable pockets and macro-voids using spin coating and post-heating, allowing for high oil uptake capacity and mechanical strength, which can be stored in a compressed form and reused after oil sorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional extrusion methods are used to produce oil sorbent films, then the films can be made with microporous structure, but the thickness is limited to around 10 μm which restricts oil uptake capacity
Solution Approach 1:
The patent introduces a dual-pore structure system comprising both micropores (from conventional extrusion) and macro-voids (from bubble template method). The macro-voids serve as large-capacity storage spaces for oil, while micropores provide diffusion pathways. This hierarchical porous structure enables the thin film to achieve high oil uptake capacity without increasing thickness, directly resolving the contradiction between film thickness and oil uptake capacity.
Solution Approach 2:
The patent transitions from a conventional single-phase dense film structure to a multi-dimensional hierarchical porous structure by introducing macro-voids as a new structural dimension. The bubble template method creates three-dimensional macro-void networks distributed throughout the film, adding vertical and lateral dimensional complexity that dramatically increases oil storage capacity within the same thickness constraint.
2Quantity of substance
If wet extrusion or dry extrusion processes are used to create microporous thin films, then pores can be formed, but the preparation method becomes energy-intensive, laborious, and expensive involving multiple steps
Solution Approach 1:
The patent merges the pore-forming agent incorporation step with the film casting process itself. The bubble template method allows pore-forming agents (gas bubbles or volatile liquids) to be integrated into the polymer matrix during a single casting operation, eliminating the need for separate extrusion, stretching, and solvent extraction steps required by conventional methods. This consolidation dramatically simplifies the manufacturing process while maintaining high porosity.
Solution Approach 2:
The patent uses bubble templates (gas bubbles or volatile liquid droplets) as intermediary agents to create pores. These intermediaries are easily introduced during casting and subsequently removed by simple heating or drying, leaving behind clean macro-void structures. This intermediary approach avoids the complex chemical extraction processes required by conventional pore-forming methods, reducing manufacturing complexity and energy consumption.
3Length of stationary object
If thin film sorbents with micropores are used, then the film thickness is reduced, but the oil uptake capacity is limited due to the small volume of micropores
Solution Approach 1:
The patent segments the pore structure into two distinct functional zones: micropores for rapid oil diffusion and macro-voids for bulk oil storage. This segmentation allows each pore type to specialize in its optimal function - micropores provide high surface area for quick oil absorption, while macro-voids provide large volume for sustained storage. The combined effect achieves high oil uptake capacity in thin films without relying on increased thickness.
Solution Approach 2:
The patent creates a nested hierarchical structure where micropores are distributed within and around the macro-voids. The micropore network penetrates into the walls separating macro-voids, creating a multi-scale nested porous architecture. This nesting arrangement maximizes the utilization of available space, allowing thin films to achieve high oil uptake capacity by efficiently packing both micropore and macro-void structures within the limited thickness.
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 enables the production of thin films with high oil uptake capacity, mechanical strength, and efficient oil sorption, allowing for 98% oil recovery and reuse, addressing the limitations of existing sorbents in terms of thickness, energy consumption, and space efficiency.
Implementation Method 1
applying the well-dispersed solution onto the solid substrate through spin coating to form a thin film on the solid substrate
Implementation Method 2
extracting the swellable pocket forming agent from the peeled thin film by washing the peeled thin film in water
Implementation Method 3
a combination of pores, macro-voids, and swellable pockets to maximize diffusion, sorption, and retention mechanism
Implementation Method 4
a combination of pores, macro-voids, and swellable pockets to maximize diffusion, sorption, and retention mechanism
Data Source
AI summary
Freestanding porous polyethylene thin film, and a method for preparing a freestanding porous polyethylene thin film. The method includes dissolving polyethylene in an organic solvent to form a solution under reflux conditions; adding a swellable pocket forming agent to the solution and mixing the solution until the swellable pocket forming agent is well-dispersed therein; applying the well-dispersed solution onto a solid substrate through spin coating to form a thin film on the solid substrate; peeling the thin film off the solid substrate; and extracting the swellable pocket forming agent from the peeled thin film by washing the peeled thin film in water, thereby obtaining a freestanding porous polyethylene thin film with swellable pockets, macro-voids, and micropores. The freestanding porous polyethylene thin film can be used as an oil sorbent. The freestanding porous polyethylene thin film has about 500 to about 800 swellable cavities per cm2.