Helix Formation in the Polymer Brush

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• 作者：Mark Kastantin ; Matthew Tirrell
• 刊名：Macromolecules
• 出版年：2011
• 出版时间：June 28, 2011
• 年：2011
• 卷：44
• 期：12
• 页码：4977-4987
• 全文大小：1000K
• 年卷期：v.44,no.12(June 28, 2011)
• ISSN：1520-5835

文摘

This work considers the physics of a brush formed by polymers capable of undergoing a helix鈥揷oil transition. A self-consistent field approximation for strongly stretched polymer chains is used in combination with a lattice model of the interaction energy in helix鈥揷oil mixtures. Crowding-induced chain stretching stabilizes helix formation at moderate tethering densities while high tethering density causes sufficiently strong stretching to unravel segments of the helix, resulting in distinct layers of monomer density and helical content. Compared to a random-coil brush at low-to-moderate tethering density, a helicogenic brush is less resistant to compression in the direction perpendicular to stretching due to easy alignment of helices and fewer unfavorable interactions between helical segments. At higher tethering density, the above-mentioned stretch-induced decrease in helical content resists further compression. The proposed model is useful for understanding an emerging class of biomaterials that utilize helix-forming polymer brushes to induce shape changes or to stabilize biofunctional helical peptide sequences.