Fig 1

(a) Tendency of published papers on PNIPAm cross-inked thermo-responsive nanofibers mats published in Web of Science core journals collection 2013–2023, up to March 2023; (b) application of PNIPAm thermo-responsive nanofibers mats."

Fig 2

(a) Plane SEM image and (b) cross-section diagrams of pure PNIPAm nanofibers 13; (c) plane SEM image of ecovio®/PNIPAm nanofibers 22; (d) nanofibers cross-section SEM image 23. (a, b) Adapted with permission from Ref. 13, Copyright 2008 Elsevier Inc.; (c) Adapted with permission from Ref. 22, Copyright 2022 SciELO; (d) Adapted with permission from Ref. 23, Copyright 2019 American Chemical Society."

Fig 3

(a) SEM image of PNIPAm/35% ZnO nanofibers mat, (b) the average fiber diameters with different ZnO contents 25; (c) molecular mechanism diagram of the thermo-responsive of PNIPAm/PS nanofibers mats, (d) temperature dependences of the WCAs for PNIPAm/PS composite nanofibers mats Ⅰ, Ⅱ and Ⅲ in which the fraction of PNIPAm versus PS is 10%, 60% and 20%, respectively 12; (e) SEM image of 16.0% (w/v) PNIPAm/1.0% (w/v) PEO nanofibers mats, (f) the in vitro release profiles of VB12 from the PNIPAm/PEO nanofibers mats 26. (a, b) Adapted with permission from Ref. 25, Copyright 2015 Elsevier Inc.; (c, d) Adapted with permission from Ref. 12, Copyright 2008 John Wiley and Sons; (e, f) Adapted with permission from Ref. 26 Copyright 2011 Elsevier Inc."

Table 1

Properties and application scenarios of poly(N-isopropylacrylamide) non-cross-linked thermo-responsive nanofibers mats."

Table 2

Cross-linking methods, properties and application scenarios of poly(N-isopropylacrylamide) thermo-responsive nanofibers mats."

Fig 4

(a) Mechanism of PNIPAm and SA polymerization; (b) dry and underwater SEM images of HPBO/NIPAm/SA nanofibers mats with different component ratios; (c) variation of the PL spectra of P4 nanofibers mats with temperature using a Zn2+ concentration of 10−4 mol∙L−1. The two inset figures show confocal images of the nanofibers at 40 and 10 ℃ 35. (b) (c) Adapted with permission from Ref. 35, Copyright 2014 Royal Society of Chemistry."

Fig 5

Chemical cross-linking mechanism of PNIPAm-based temperature-sensitive nanofibers mats: (a) OpePOSS as cross-linking agent16; (b) NHS/EDC as cross-linking agent; (c) ABP as cross-linking agent; (d) esterification reaction; (e) self-condensation reaction; (f) ester-amine reaction; (g) egg protein heating cross-linking; (h) in situ cross-linking. (a) Adapted with permission from Ref. 16, Copyright 2011 Royal Society of Chemistry."

Fig 6

(a, b) Effect of the presence of EMI on the morphology of PNIPAm/OpePOSS nanofibers mats 16; (c) XPS patterns of PNIPAm/PCL cross-linked nanofibers mats after 1 h, 2 h and 3 h immersion in water 63; (d) the nanofibers mats obtained from p(NIPAm-ABP) (left) and pure PNIPAm (right) were immersed in water at 20 ℃ for given times, (e) molecular weight of p(NIPAm-ABP) from different molar ratio between NIPAm and ABP 64; SEM images of p(NIPAm-co-β-CD)/p(NIPAm-co-MAA) nanofibers mats after (f) 4 h, (g) 8 h, (h) 12 h crosslinking 68; images of (i) dry state, (j) p(NIPAm-co-NMA) and p(NIPAm-co-NMA)/ChNWs nanofibers mats in water 69. (a, b) Adapted with permission from Ref. 16, Copyright 2011 Royal Society of Chemistry; (c) Adapted with permission from Ref. 63, Copyright 2016 John Wiley and Sons; (d, e) Adapted with permission from Ref. 64, Copyright 2019 Elsevier Inc.; (f, g, h) Adapted with permission from Ref. 68, Copyright 2020 Elsevier Inc.; (i, j) Adapted with permission from Ref. 69, Copyright 2018 American Chemical Society."

Fig 7

Morphology of AuNRs/PNIPAm/OpePOSS nanofibers mats at (a) 0 s, (b) 2.5 s under light, (c) "current-time" amplification signal when the thermal/optical control switch is turned on and off 73; (d) morphology of p(NIPAm-ABP)/TPU bilayer nanofibers mats in different states and response rates 74; the effect of cross-linker ratios on (e) swelling and (f) de-swelling ratios for p(NIPAm-ABP) nanofibers mats 64; (g) temperature dependence of optical transmittance of fibers mats with different degrees of cross-linked, (h) variations of swelling ratio for the cross-linked nanofibers mats in response to cycles of temperature alternation between 10 and 45 ℃ 76; (i) effect of Am content on the LCST of PNIPAm-NMA-Am nanofibers mats, (j) release profiles of curcumin from PNIPAm-NMA-Am10 cross-linked nanofibers mats 77. (a, b, c) Adapted with permission from Ref. 73, Copyright 2017 American Chemical Society; (d) Adapted with permission from Ref. 74, Copyright 2015 John Wiley and Sons. (e, f) Adapted with permission from Ref. 64, Copyright 2019 Elsevier Inc.; (g, h) Adapted with permission from Ref. 76, Copyright 2012 iopscience; (i, j) Adapted with permission from Ref. 77, Copyright 2019 Elsevier Inc."

Fig 8

Timeline of PNIPAm cross-linked thermo-responsive nanofibers mats development."