Dynamic Light Scattering Studies on the Effect of 1-Alkanols, Alkanediols and Alkoxyethanols on the Micelles of a Moderately Hydrophobic/Hydrophilic PEO-PPO-PEO Triblock Copolymer
Parekh, P; Bahadur, P
| HERO ID | 4683779 |
|---|---|
| In Press | No |
| Year | 2011 |
| Title | Dynamic Light Scattering Studies on the Effect of 1-Alkanols, Alkanediols and Alkoxyethanols on the Micelles of a Moderately Hydrophobic/Hydrophilic PEO-PPO-PEO Triblock Copolymer |
| Authors | Parekh, P; Bahadur, P |
| Journal | Journal of Surfactants and Detergents |
| Volume | 14 |
| Issue | 3 (Jul 2011) |
| Page Numbers | 425-432 |
| Abstract | The results on changes in the apparent hydrodynamic diameter (D^sub h^) of micelles in a solution containing 5% of a moderately hydrophobic/hydrophilic triblock PEO-PPO-PEO copolymer in the presence of several hydroxyl compounds at 23 °C from dynamic light scattering (DLS) are reported. Distribution plots show micelles with hydrodynamic diameter ~ 17 nm and low polydispersity (<0.1) except at low concentrations where a unimer peak (~ 4 nm) was also noticed. These additives increase/decrease the micelle size and show micellar transition depending upon their hydrophilicity/hydrophobicity. The results are discussed in terms of the effect of the additives on altering water structure and their partitioning in micelle. Short chain alcohols (C^sub 1^-C^sub 3^) increase solvation of PEO and thus increase micelle hydrodynamic size while higher alcohols, initially reduce D^sub h^ due shrinkage of PEO followed by micellar growm at higher concentrations. Among αω-alkanediols, C^sub 2^ and C^sub 4^ diols increase micelle size by immobilizing water sphere around the micelles whereas higher diols form wicket like structures and reside in palisade layer. Isomeric hexanediols (1,2; 1,5; 2,5 and 1,6) alter micelle size in different ways depending on their hydrophobicity. In C^sub 6^EO^sub m^ (m = 0, 1, 2), as the number of EO group increases, it becomes more hydrophilic and increases D^sub h^ at higher concentration. Addition of a hydrophobic triblock copolymer leads to unfavorable mixing with a moderately hydrophobic/hydrophilic triblock copolymer which results in increase in size, while the addition of a hydrophilic counterpart increases the average hydrodynamic size and follows appearance of unimer peak. [PUBLICATION ABSTRACT] |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Keyword | Polymers; Copolymers; Temperature; Molecular weight |