Tummala Naga Rajesh, Striolo Alberto
School of Chemical, Biological, and Materials Engineering, The University of Oklahoma, Norman, Oklahoma 73019, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Aug;80(2 Pt 1):021408. doi: 10.1103/PhysRevE.80.021408. Epub 2009 Aug 28.
The effect of substrate curvature on surfactant self-assembly has been studied using all-atom molecular-dynamics simulations. We studied aqueous sodium-dodecyl-sulfate (SDS) surfactants on graphite, on the outer surface of single walled carbon nanotubes (SWNTs) and within SWNTs. Our results reveal that although the chemical nature of the substrates is constant, the self-assembled structures change significantly as the curvature varies. For example, at large surface density, SDS surfactants yield micellar structures on graphite, layered self-assemblies outside SWNTs, and cylindrical lamellar structures inside SWNTs. Changes in substrate curvature as well as surfactant surface density affect significantly surfactant orientation and, more importantly, headgroup-headgroup distribution, headgroup-counterion packing, and counterion residence time next to the headgroups.
已使用全原子分子动力学模拟研究了基底曲率对表面活性剂自组装的影响。我们研究了十二烷基硫酸钠（SDS）水溶液在石墨上、单壁碳纳米管（SWNTs）外表面以及SWNTs内部的情况。我们的结果表明，尽管基底的化学性质保持不变，但随着曲率的变化，自组装结构会发生显著变化。例如，在高表面密度下，SDS表面活性剂在石墨上形成胶束结构，在SWNTs外部形成层状自组装结构，在SWNTs内部形成圆柱形层状结构。基底曲率以及表面活性剂表面密度的变化会显著影响表面活性剂的取向，更重要的是，会影响头基-头基分布、头基-抗衡离子堆积以及头基附近抗衡离子的停留时间。
