Electrospun Polymer Nanofibers: Processing, Properties, and Applications

by

📷Abdulhamid Al-Abduljabbar

*📷 and

📷Irfan Farooq

Department of Mechanical Engineering, King Saud University, Riyadh 11421, Saudi Arabia

*

Author to whom correspondence should be addressed.

Polymers 2023, 15(1), 65; https://doi.org/10.3390/polym15010065

Received: 10 November 2022/ Revised: 8 December 2022/ Accepted: 13 December 2022/ Published: 23 December 2022

(This article belongs to the Special Issue Preparation of Polymer Nanofiber and Its Application)

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Abstract Electrospun polymer nanofibers (EPNF) constitute one of the most important nanomaterials with diverse applications. An overall review of EPNF is presented here, starting with an introduction to the most attractive features of these materials, which include the high aspect ratio and area to volume ratio as well as excellent processability through various production techniques. A review of these techniques is featured with a focus on electrospinning, which is the most widely used, with a detailed description and different types of the process. Polymers used in electrospinning are also reviewed with the solvent effect highlighted, followed by a discussion of the parameters of the electrospinning process. The mechanical properties of EPNF are discussed in detail with a focus on tests and techniques used for determining them, followed by a section for other properties including electrical, chemical, and optical properties. The final section is dedicated to the most important applications for EPNF, which constitute the driver for the relentless pursuit of their continuous development and improvement. These applications include biomedical application such as tissue engineering, wound healing and dressing, and drug delivery systems. In addition, sensors and biosensors applications, air filtration, defense applications, and energy devices are reviewed. A brief conclusion is presented at the end with the most important findings and directions for future research.polymer nanofibers; electrospinning; polymer processing; mechanical properties; biomedical application; energy storage separation; composite materials functional nanofiberKeywords:

1. Introduction Interest in polymer nanofibers has increased rapidly in the recent few decades. The main drivers include not only the improved properties due to high aspect ratio and surface area to volume, but also the manufacturability and diversity of applications. Some sources [1] attribute nanofibers’ class to fibers with a ratio of length to thickness in the order of one thousand. Others classify nanofibers as nanomaterials that have at least one dimension of 100 nm or less [2,3]. Since the cross-section area of the nanofiber is meant here, the nanoscale is actually in two dimensions. A nanofiber with a diameter of ∼100 nm can have a specific surface area up to 1000 m2/g [4].Although meso- and nano-porous materials, such as adsorbent granules and powders, can achieve large surface areas exceeding 2000 m2/g, fibers are easier to handle and more suitable for use in numerous crucial applications in contrast with powders. The benefit of large surface areas in organic fibers is frequently coupled with the flexibility of surface functionality, which can be utilized for a variety of applications, for example, biomedical applications, effective filtration, smart textiles, and improved fiber–matrix interaction for composite reinforcement applications [5]. Polymeric materials are widely utilized to manufacture nanofibers because of many attractive features and properties such as low cost, light weight, easy and diverse processing techniques, and flexibility of utilization and recyclability [6,7,8]. Combined characteristics found in polymer nanofibers make them strong candidates for such diverse and important applications [9,10]. Polymeric fibers’ remarkable features improve as the fiber diameter decreases from micrometer to submicron or nanometer. These include an extremely high surface area to volume ratio, pliability in surface functionalities, and superior mechanical properties compared to other materials. Due to their exceptional characteristics, polymer nanofibers are favored for a variety of applications [11].Nanofibers can be produced by selecting the proper combination of polymers and additives and by using appropriate production techniques based on several essential characteristics that have an impact on meeting the criteria of the intended particular application area [12]. Among the different techniques which have been developed to process polymer nanofibers are phase separation or inversion [13,14], spinneret-based tunable engineered parameters [15], self-assembly polymerization [16], template synthesis [17], hot stretching [18], and electrospinning [19,20]. A comparison of different techniques for production of polymer nanofibers including electrospinning methods is shown in Table 1. Electrospinning is considered as the most prominent method to process polymer nanofibers [21]. Electrospinning is a relatively simple process that uses diverse polymers. Moreover, it produces long continuous nanofibers, and it can feasibly generate aligned nanofibers. Using this technique, a huge range of polymers can be processed to successfully reduce fiber diameter to nanometer scale, with the possibility of scaling up production [10,11,22].Table 1.Different techniques for polymer nanofibers production, from different sources.📷

Hamed Fayaz Rouhi

If your goal is to synthesize metal oxide-based photodetectors using the electrospinning method, you can use available polymers such as Polyvinylpyrrolidone (PVP) or polyvinyl alcohol.

The choice of polymer should be based on your project's specific requirements. These are some examples, such as biocompatibility, mechanical properties, degradation rate, and application. These are some examples of polymers.