Abstract
Light scattering techniques, video particle-tracking microrheology, and bulk rheology were employed to examine the structure and dynamics of a series of alternating sodium maleate copolymers with moderately hydrophobic comonomers (diisobutylene, styrene, and isobutylene) in aqueous solutions. The scaling dependence of the specific viscosity (ηsp) on the polyelectrolyte concentration (c) was studied with and without added salt; similar trends were found in both conventional rheology and particle-tracking microrheology measurements, showing good performance of the technique with flexible polyelectrolytes. Furthermore, with dynamic light scattering performed in high added salt conditions, we examined the behavior of the amplitude of the fast mode, which is in agreement with scaling predictions. In contrast, the slow modes are not understood and display three separate behaviors for the wavevector q dependence of the decay rate (Γ), depending on the comonomer; superdiffusive (Γ ∼ q2.7, isobutylene) possibly because of sticky aggregates, wavevector independent (Γ ∼ q0, styrene) most likely because of coupled polyion-ion diffusion and diffusive (Γ ∼ q2.0, diisobutylene) presumably because these aggregates are not sticky. The hydrophobicity of the comonomer appears to switch the aggregation process between "open," "closed," and "non" association for isobutylene, diisobutylene, and styrene respectively.
Original language | English (US) |
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Pages (from-to) | 774-785 |
Number of pages | 12 |
Journal | Journal of Polymer Science, Part B: Polymer Physics |
Volume | 45 |
Issue number | 7 |
DOIs | |
State | Published - Apr 1 2007 |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Polymers and Plastics
- Materials Chemistry