Reentrant swelling behavior of thermosensitive N-isopropylacrylamide nano-sized gel particles

✍ Scribed by Sang Chul Jung; Suk Yung Oh; Young Chan Bae

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 475 KB
• Volume: 50
• Category: Article
• ISSN: 0032-3861
• DOI: 10.1016/j.polymer.2009.05.011

✦ Synopsis

The closed-loop phase diagram of poly N-isopropylacrylamide (PNIPA) in a water-N,N-dimethylformamide (DMF) system was measured by thermooptical analysis (TOA). The reentrant swelling behavior of N-isopropylacrylamide (NIPA) nano-sized gel particles in the water-DMF system was measured by using photon correlation spectroscopy (PCS) technique. Theoretically, a modified double lattice model (MDL) can be used to describe the closed-loop phase behavior of linear PNIPA in water-DMF systems. For crosslinked NIPA nano-sized gel particles in a water-DMF system, we combined MDL theory for the mixing contribution and Flory-Erman theory for the elastic contribution. Molecular interaction parameters obtained from the PNIPA solution were used to directly predict the swelling-ratio curves for the NIPA gel. Using our model, the calculated results were in good agreement with the experimental data using only one adjustable parameter.