<p>We investigate the entanglement dynamics of salt-free aqueous solutions of poly(sodium styrenesulfonate) (NaPSS) across a range of molecular weights, focusing on the semidilute entangled regime. By combining conventional bulk shear rheometry with diffusing wave spectroscopy (DWS) microrheometry, we characterize key parameters, including the entanglement concentration, plateau modulus, reptation time, and Rouse time of entanglement strands. A clear crossover from polyelectrolyte-like to neutral polymer-like behavior is identified as the degree of polymerization decreases, corresponding to a critical monomer concentration <i>c</i><sub>D</sub>&#xa0;~&#xa0;0.3 M and a critical degree of polymerization <i>N</i><sup>*</sup>&#xa0;~&#xa0;6000. The experimental scaling relationships closely agree with the predictions from the Dobrynin model. Our findings provide new insights into the long-standing debate on the entanglement dynamics of polyelectrolytes and establish a framework for analyzing and controlling the solution properties of salt-free polyelectrolytes in the semidilute entangled regime. Moreover, they demonstrate the power of DWS microrheology for probing complex rheological behavior in polyelectrolyte systems.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Microrheological study on the entanglement dynamics of salt-free polyelectrolyte solutions in the semidilute entangled regime

  • Atsushi Matsumoto,
  • Ikuto Kato,
  • Chi Zhang,
  • Shinji Sugihara,
  • Yasushi Maeda,
  • Frank Scheffold,
  • Amy Q. Shen

摘要

We investigate the entanglement dynamics of salt-free aqueous solutions of poly(sodium styrenesulfonate) (NaPSS) across a range of molecular weights, focusing on the semidilute entangled regime. By combining conventional bulk shear rheometry with diffusing wave spectroscopy (DWS) microrheometry, we characterize key parameters, including the entanglement concentration, plateau modulus, reptation time, and Rouse time of entanglement strands. A clear crossover from polyelectrolyte-like to neutral polymer-like behavior is identified as the degree of polymerization decreases, corresponding to a critical monomer concentration cD ~ 0.3 M and a critical degree of polymerization N* ~ 6000. The experimental scaling relationships closely agree with the predictions from the Dobrynin model. Our findings provide new insights into the long-standing debate on the entanglement dynamics of polyelectrolytes and establish a framework for analyzing and controlling the solution properties of salt-free polyelectrolytes in the semidilute entangled regime. Moreover, they demonstrate the power of DWS microrheology for probing complex rheological behavior in polyelectrolyte systems.