Prasad Shishir, Jiang Zhang, Sinha Sunil K, Dhinojwala Ali
Department of Polymer Science, The University of Akron, Akron, Ohio 44325, USA.
Phys Rev Lett. 2008 Aug 8;101(6):065505. doi: 10.1103/PhysRevLett.101.065505. Epub 2008 Aug 7.
We have studied the structure of a novel crystalline surface monolayer on top of a disordered melt of the same material [poly(n-alkyl acrylate)s] using grazing incidence x-ray diffraction. The grazing incidence x-ray diffraction, surface tension, and bulk latent heat results show that side chains crystallize except the nine methylene units of the alkyl side chains closest to the polymer backbone. The partial crystallinity along with a thicker surface layer, due to the additional length of the linker group, explains why the difference between the surface order-to-disorder transition temperature and bulk melting temperature increases with a decrease in the length of the alkyl side chain.
我们使用掠入射X射线衍射研究了在相同材料[聚丙烯酸正烷基酯]的无序熔体之上的新型晶体表面单分子层的结构。掠入射X射线衍射、表面张力和体相潜热结果表明，除了最靠近聚合物主链的烷基侧链的九个亚甲基单元外，侧链会结晶。由于连接基团的额外长度，部分结晶性以及更厚的表面层解释了为什么表面有序-无序转变温度与体相熔点之间的差异会随着烷基侧链长度的减小而增加。
