Stimuli-Responsive Self-Immolative Polymer Nanofiber Membranes Formed by Coaxial Electrospinning

Abstract

The first self-immolative polymer (SIP) nanofiber membrane is demonstrated in this report, in which the immolation can be triggered by external stimulus. Electrospun SIP/polyacrylonitrile (PAN) fibers provide depolymerization that is ∼25 times quicker and more responsive (i.e., immolation) than that of a cast film in the triggering condition. Depolymerization of SIP in the SIP/PAN blended fiber membrane results in the transition of the surface properties from hydrophobic (∼110°) to hygroscopic (∼0°). Triggered release of encapsulated functional molecules was demonstrated using coaxially electrospun fiber membrane made of a SIP/PAN blend sheath and polyvinylpyrrolidone/dye core. Coaxial fibers with the SIP/PAN sheath provide minimal release of the encapsulated material in nontriggering solution, while it releases the encapsulated material instantly when the triggering condition is met. Its versatility has been strengthened compared to that of non-SIP coaxial fibers that provide no triggering reaction by external stimulus.

Coaxial Electrospinning Formation of Complex Polymer Fibers and their Applications

“…Upon adding TFA, encapsulated dye was released swiftly and reached 100 % within a few hours. Depolymerized SIP was also abruptly released indicating a quick sheath depolymerization . Since this report demonstrated the concept of SIP core‐sheath nanofibers, possibly other SIP materials triggered by UV light, enzyme, or specific ions can be adopted for novel application developments.…”

Air‐Blowing‐Assisted Coaxial Electrospinning toward High Productivity of Core/Sheath and Hollow Fibers

“…The detailed optimized electrospinning parameters were summarized in Table 1 . When applying an air‐blowing rate of 30 L min –1 , and a voltage of 28 kV, the total flow rate for electrospinning could reach to 2.5 mL h –1 , which is already much higher than some normal coaxial electrospinning process without air‐blowing‐assistance, such as PLA‐PVA (0.3 mL h –1 ), TPU‐PS (0.84 mL h –1 ), and PVP‐PAN (1.0 mL h –1 ) . With the same air blowing rate of 30 mL min –1 , but increasing the voltage to 38 kV, the total flow rate for PAN‐TPU coaxial electrospinning could be up to 5.0 mL h –1 , which is already higher than the largest value of 4 mL h –1 for normal coaxial electrospinning of PEG‐PBS system .…”

“…already much higher than some normal coaxial electrospinning process without air-blowing-assistance, such as PLA-PVA (0.3 mL h -1 ), [20] TPU-PS (0.84 mL h -1 ), [21] and PVP-PAN (1.0 mL h -1 ). [22] With the same air blowing rate of 30 mL min -1 , but increasing the voltage to 38 kV, the total flow rate for PAN-TPU coaxial electrospinning could be up to 5.0 mL h -1 , which is already higher than the largest value of 4 mL h -1 for normal coaxial electrospinning of PEG-PBS system. [23] When further increasing the air-blowing rate to 60 L min -1 , the flow rate for PAN and TPU could be up to 3.0 and 9.0 mL h -1 , respectively, suggesting a total flow rate of 12.0 mL h -1 , which could be the highest value till now for the coaxial electrospinning.…”

“…Figure 5 compared the total flow rate related productivity from conventional coaxial electrospinning and coaxial electrospinning with air-blowing-assistance in this work and the corresponding data were summarized in Table 2. It can be seen that conventional coaxial electrospinning usually has a total flow rate below 5 mL h -1 and productivity below 1 g h -1 , such as for the coaxial systems of PLA-PVA, [20] PLGA/ HA, [25] TPU-PS, [21] PCL-chitosan, [26] PVP-PAN, [22] PCL-zein, [27] HPMC-solvent, [28] PVP-PEG, [2] PMMA-PAN, [29] PCL-gelatin-MA, [30] and PEG-PBS. [23] As comparison, all the examples in this work by air-blowing-assisted electrospinning showed a large total flow rate in the range of 5.8-12 mL h -1 and high productivity in the range of 1.16-3.6 g h -1 .…”

Neoteric Conjugative Electrospinning towards Alloplastic Nanofiber Yarns Affording Enhanced Upconversion Luminescence and Tailored Magnetism

“…As a raw material, one‐dimensional nanofibers are widely used for designing and constructing products with two‐dimensional and three‐dimensional structures . These downstream products have unique optical, mechanical, electrical, magnetic and biological properties, which are widely used in the photocatalyst materials, biological textiles, electronic devices, gas‐sensitive materials and other fields. In recent years, the commonly used electrospinning templates are polyvinyl pyrrolidone (PVP), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyethylene oxide (PEO), etc.…”