ELECTROSPUN NANOFIBERS FOR WATERPROOF AND BREATHABLE CLOTHING

Functional garments with robust waterproofness and breathability have attracted wide attention. Waterproof and breathable (W&B) functional fabrics have been developed for use in clothing to protect the wearer from environmental rain and snow, and at the same time providing a good level of comfort under many extreme climatic conditions (Jeong and An, 2002; Mukhopadhyay and Midha, 2008a; Pei et al., 2017; Sarkar et al., 2017). The current W&B fabrics include high-density woven fabrics, coated fabrics, and laminated fabrics (Mukhopadhyay and Midha, 2008b; Wu et al., 2011). High-density woven fabrics owe their good moisture permeability to the thin and smooth yarns that are usually made from microfifibers, but the waterproof property is relatively poor. The waterproofness of the coated fabrics is good, due to the nonporous structure, but the moisture permeability is not very good. As one kind of the mainstream products, laminated fabrics have excellent comprehensive waterproofness and breathability compared with the two former fabrics , which is due to the core layer of the fabric made of W&B membranes (Cui et al., 2016; Yin et al., 2016). The permeability to water vapor but resistance to water droplets makes functional membranes applicable not only in the textile and clothing industry, but also in medical and health care, construction of external walls, and the aerospace and aquaculture industries (Branson and Sweeney, 1991; Lalia et al., 2013; Rother et al., 2015; Zhang and Ji, 2009).

The commercial W&B membranes are classifified into two types, comprising polytetraflfluoroethylene (PTFE) stretchable microporous membranes and thermoplastic polyurethane (TPU) hydrophilic nonporous membranes (Dieval and Viallier, 2012; Gugliuzza and Drioli, 2013). The disadvantages of PTFE membranes are the high price and the diffificulties in recycling. As for TPU hydrophilic nonporous membranes, the defect is the discomfort caused by the low water vapor permeability for the wearer (Lomax, 2007). In fact, there is a negative relationship between protective properties and comfort, which greatly limits the practical application of W&B membranes. Therefore, it is very urgent to fifind a new strategy to fabricate W&B membranes with high performance to meet the demands of protection and comfort simultaneously

Electrospinning, as one versatile technique to produce porous nanofifibrous membranes, has gained considerable interest attributed to the wide range of raw materials, low power consumption, and convenience in creating a hydrophobic surface (Chronakis, 2005; Wang et al., 2013; Si et al., 2015). Apart from this, the other unique advantages, such as low weight, small pore size, high porosity, interconnected tortuous channels, and controllable porous structure (Huang et al., 2003; Sahay et al., 2012; Teo and Ramakrishna, 2006), have helped electrospinning become an effective strategy to fabricate functional W&B membranes. More and more groups have started to enter the fifield of electrospun W&B clothing, which has resulted in a dramatic increase in pub lications. But there are some great challenges in the fabrication of electrospun W&B membranes (Ahn et al., 2011; Lee et al., 2003). For example, hydrostatic pressure and water vapor transmission cannot be improved simultaneously, flfluorine-containing materials lead to environmental contamination (Arvaniti et al., 2015), and excellent hydrophobic and corrosionresistant membranes cannot be prepared. The porous structure and surface wettability of the fifibrous membranes can be easily regulated by changing several parameters, including solution properties (conductivity, viscosity, and surface tension), processing parameters (receiving distance, voltage, injection rate, and needle diameter), and environmental parameters (temperature and relative humidity), which makes it easier to prepare membranes with better equilibrium of waterproofness and breathability (Pelipenko et al., 2013; Yao et al., 2016; Ding and Yu, 2011). Electrospun nanofifibers with various morphologies and structures have been fabricated to exhibit W&B performance, and we focus on the electrospun W&B membranes with respect to various polymers in this chapter.

Paper link：https://www.sciencedirect.com/book/9780323512701/electrospinning-nanofabrication-and-applications