(558e) Solvent Response of Mixed Polymer Brushes

"Smart" materials, also known as self-responsive materials,  has attracted increasing attention in recent years due to its broad application such as controlled drug-delivery, micro- and nanofluidics, biocompatible material, chemical sensors, antifouling coatings. These materials can respond to the external signal or environment such as temperature, light, pH, solvent selectivity, electric field, etc.^1-3

Polymer brushes,⁴ especially copolymer brushes or mixed polymer brushes, is considered as a novel and robust way of creating smart surfaces.^1-3 Recent advances in the synthesis of polymer brushes has made the control of the chain length, the monomer fraction, and the grafted density become possible.^5-8 The self-assembly of mixed polymer brushes towards the solvents has special interest because of vast parameter space including molecular weight, grafted densities, solvents selectivity can be easily employed to create rich phase diagram in that system.^7,8

We have performed density functional theory (DFT) calculation to study solvent response of mixed polymer brushes in 1-D (Dimension). To be simple, we assume no lateral segregation happens and only consider the implicit solvent here. We set the different interaction energy for each polymer brush to simulate their different response towards the solvents. A transition was found by increasing the chain length of one component while fixing the other's. We also study the solvent selectivity, the composition effect on the transition.

References

¹                      I. Luzinov, S. Minko, and V. V. Tsukruk, Soft Matter 4, 714 (2008).

²                      M. A. C. Stuart, W. T. S. Huck, J. Genzer, M. Müller, C. Ober, M. Stamm, G. B. Sukhorukov, I. Szleifer, V. V. Tsukruk, M. Urban, F. Winnik, S. Zauscher, I. Luzinov, and S. Minko, Nature Materials 9, 101 (2010).

³                      T. P. Russell, Science 297, 964 (2002).

⁴                      S. T. Milner, Science 251, 905 (1991).

⁵                      P. Mansky, Y. Liu, E. Huang, T. P. Russell, and C. Hawker, Science 275, 1458 (1997).

⁶                      C. Xu, T. Wu, C. M. Drain, J. D. Batteas, M. J. Fasolka, and K. L. Beers, Macromolecules 39, 3359 (2006).

⁷                      B. Zhao, Langmuir 20, 11748 (2004).

⁸                      B. Zhao, R. T. Haasch, and S. Maclaren, J. Am. Chem. Soc 126, 6124 (2004).