Synthesis of stimuli‐responsive macroazoinitiators and their use as an inistab toward hairy polymer latex particles |
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| Authors: | Syuji Fujii Yuichi Kakigi Motomichi Suzaki Shin‐Ichi Yusa Masahiro Muraoka Yoshinobu Nakamura |
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| Institution: | 1. Department of Applied Chemistry, Osaka Institute of Technology, 5‐16‐1 Ohmiya, Asahi‐ku, Osaka 535‐8585, Japan;2. Graduate School of Engineering, University of Hyogo, 2167, Shosha, Himeji, Hyogo 671‐2280, Japan |
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| Abstract: | Stimuli‐responsive macroazoinitiators with central azo unit have been synthesized by atom transfer radical polymerization (ATRP) of 2‐(dimethylamino)ethyl methacrylate or 2‐(diethylamino)ethyl methacrylate in 2‐propanol at 25 °C. The mean degree of polymerization of the polymer chains besides the azo group was fixed between 25 and 60. 1H NMR, gel permeation chromatography, UV‐Vis spectrophotometer, and surface tensiometer were used to characterize the stimuli‐responsive macroazoinitiators in terms of their chemical structure, molecular weight, polydispersity, and pH‐responsive behavior, respectively. Eventually, dispersion polymerization of styrene using the poly2‐(diethylamino)ethyl methacrylate] (PDEA) macroazoinitiator as an inistab (initiator + stabilizer) in 2‐propanol medium was conducted. Near‐monodisperse 98 nm polystyrene (PS) latex particles with pH‐responsive PDEA hair were successfully synthesized. The PS latex particles with the PDEA hair can be dispersed in acidic aqueous media where the PDEA hair was protonated and was solvated, and can be flocculated in basic aqueous media where the PDEA hair was deprotonated and was precipitated. This dispersion‐flocculation cycle was reversible. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3431–3443, 2009 |
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| Keywords: | initiators radical polymerization stimuli‐sensitive polymers |
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