Absorption Properties of Microgel-PVP Composite Nanofibers Made by Electrospinning

• Published in: Macromolecular rapid communications. 2010-01, Vol.31 (2), p.183-189
• Main Authors: Díaz, Juan Esteban, Barrero, Antonio, Márquez, Manuel, Fernández-Nieves, Alberto, Loscertales, Ignacio G.
• Format: Article
• Language: English
• Subjects: absorption; electrospinning; fibers; microgels; stimuli-sensitive polymers
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.200900534

The absorption and desorption of water, as well as the retention of certain molecules within a polymeric network, have special interest in a wide range of applications, including drug delivery, biosensing, chemical separation, catalysis, and optics. In this communication, we report the encapsulation by electrospinning of poly(N‐isopropylacrylamide)‐based monodisperse microgels within microfibers of crosslinked poly(vinylpyrrolidone), which is a hydrogel itself, up to concentrations of 40 wt.‐% of the microgels. We present an optical characterization of these composite microfibers and quantify their absorbance, which can be as large as 17 times their de‐swollen weight. Interestingly, this absorbance can be tuned by controlling the values of the temperature and the pH of the medium. Encapsulating microgels within crosslinked polymer nanofibers allows the design of composite materials that might retain the characteristics of the polymer nanofibers but whose absorbance may be tuned according to some particular ambient stimulus (i.e., temperature, pH, etc.). While the absorbance can be made as large as 17, it dramatically reduces when the stimulus disappears.