Control of thermoresponsive property of urea end‐functionalized poly(N‐isopropylacrylamide) based on the hydrogen bond‐assisted self‐assembly in water |
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| Authors: | Keita Fuchise Ryohei Kakuchi Sung‐Tso Lin Ryosuke Sakai Shin‐Ichiro Sato Toshifumi Satoh Wen‐Chang Chen Toyoji Kakuchi |
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| Institution: | 1. Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060‐8628, Japan;2. Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617, Taiwan;3. Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan |
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| Abstract: | The precise synthesis and variation in the thermoresponsive property based on the supramolecular assembly of a novel urea end‐functionalized poly(N‐isopropylacrylamide) (PNIPAM) were studied. A series of PNIPAMs with different diphenylurea groups at the chain end (X? Ph? NH? CO? NH? Ph? trz? PNIPAM: X = H, OCH3, CH3, NO2, Cl, and CF3) were synthesized by using a combination of the atom transfer radical polymerization and the copper(I)‐catalyzed azide‐alkyne cycloaddition. The cloud point of the obtained polymers depended on the hydrogen‐bonding ability of the introduced urea group. The 1H NMR measurement suggested that the obtained PNIPAM assembled in water via the intermolecular hydrogen bonding by the terminal urea group. From the dynamic light scattering and transmission electron microscopy measurements, the aggregated nanoparticles of the resulting polymer were directly observed in water at a temperature below its cloud point. The hydrogen‐bonding property of the chain end urea group was concluded to be involved in the aggregation of the PNIPAM in water, leading to the variation in its cloud point. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6259–6268, 2009 |
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| Keywords: | atom transfer radical polymerization (ATRP) lower critical solution temperature (LCST) self‐assembly stimuli‐sensitive polymers TEM urea group |
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