Abstract
We report a novel thermally responsive system from poly(butyl methacrylate)-b-poly(methacrylic acid)-b-poly(butyl methacrylate) (PBMA-b-PMAA-b-PBMA) triblock copolymer in dimethylformamide (DMF) solvent. This system shows a sol–gel transition by cooling below a critical temperature Tc. The network relaxation times of these gels rightly fall in the typical rheological experiment window, permitting us to investigate the relaxation dynamics and underlying mechanism, with a combination of linear rheology, time-resolved small-angle X-ray scattering (SAXS), and temperature-elevated nuclear magnetic resonance (NMR) measurements. Both time–temperature superposition (TTS) and time–concentration superposition (TCS) are well held in this system. The relaxation dynamics at temperatures below and above Tc are quite different, giving two different activation energies E1a and E2a, respectively. The E1a, being polymer concentration independent, is related to micelle formation of end-blocks, while the concentration depend...
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