Preparation of Super Spreading Polypropylene Fiber Membrane by Capillary Self-Assembly

The motion behavior of liquids on surfaces can bring many special properties to materials, and Super spreading is one of them. Super spreading endows the surface with excellent liquid transport performance and has shown promising application prospects in many fields, such as membrane preparation, heat dissipation, separation, etc. At present, super spreading materials can be prepared by template method, electrospinning method, sol gel method, phase separation method, etc. The surface structure of the prepared super spreading materials is fine, showing a special micro nano structure. However, this fine structure also makes the preparation cost of super spreading materials expensive and difficult to produce on a large scale. At the same time, the stability of this structure in air is poor, resulting in a short service life of super spreading materials in air. At present, there is a lack of a low-cost and large-scale production method for super spreading materials with good long-term performance. Therefore, in this paper, we propose a capillary driven self-assembly between two macromolecules using the principle of liquid capillary action between fibers and amphiphilic polymers, and use this method to prepare high-performance super spreading polymer film materials with a spreading time of less than 0.5 seconds. On this basis, further exploration was conducted on the application of super spreading polymer membranes, which were successfully applied in the fields of oil-water separation, seawater desalination, ion separation, and moisturizing materials.
In oil-water separation, the water flux of the super spreading polymer membrane reached 7.6 × 104L/（m²×h）, and the oil flux reached 1.3 × 105L/（m²×h）. A device was designed to simultaneously separate oil and water, and the impurity components in the separated oil and water were both below the saturation concentration. Due to the large specific surface area of the super spreading polymer film, its application in seawater desalination resulted in a seawater evaporation rate about 5 times that of the blank control group. Based on this, a device was designed to desalinate seawater using a low-grade heat source, and the salt content in the desalinated water has reached the standard for industrial use.