Comonomer effect: Switching the lower critical solution temperature to upper critical solution temperature in thermo‐pH sensitive binary graft copolymers. Issue 44 (25th June 2019)

• Record Type: Journal Article
• Authors: Pino‐Ramos, Victor H.; Cedillo, Gerardo; López‐Barriguete, Eduardo; Bucio, Emilio
• Is Part Of: Journal of applied polymer science. Volume 136:Issue 44(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-06-25
• Subjects: graft copolymers -- gamma radiation -- LCST -- stimuli‐responsive materials -- surface modification; Polymers -- Periodicals; Polymerization -- Periodicals; 668.9
• DOI: 10.1002/app.48170
• Languages: English
• ISSNs: 0021-8995

Abstract

ABSTRACT: Hydrophilic biocompatible surfaces can be obtained by grafting stimuli‐sensitive polymers onto commercially available medical devices. Thermo and pH‐responsive polymers are two of the most studied materials due to their potential application as drug delivery systems. Poly(N‐vinylcaprolactam) has a lower critical solution temperature (LCST) near to physiological temperature. However, when it is grafted with pH‐sensitive moieties its LCST it is affected undergoing remarkable displacements. We studied the effect of acrylic acid (AAc), 4‐vinylpyridine (4VP), and 1‐vinylimidazole (Vim) on the LCST of N‐vinylcaprolactam (NVCL) grafted onto silicone rubber (SR), and SR‐ g ‐NVCL (32.5 °C). The binary graft copolymers were obtained by ionizing grafting radiation using the simultaneous technique; the samples were characterized by Fourier transform infrared attenuated total reflectance (FTIR‐ATR), cross‐polarization magic angle spinning nuclear magnetic resonance (CP/MAS 13 C‐NMR), and thermogravimetrical analysis (TGA). LCST value was dramatically affected by the comonomer content; even it was observed the switching from LCST to upper critical solution temperature (UCST) for (SR‐ g ‐NVCL)‐ g ‐AAc and (SR‐ g ‐NVCL)‐ g ‐4VP samples. The observed behavior is rarely reported for binary graft copolymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019, 136, 48170. Abstract :