Nielsen Anne R, Jelavić Stanislav, Murray Daniel, Rad Behzad, Andersson Martin P, Ceccato Marcel, Mitchell Andrew C, Stipp Susan L S, Zuckermann Ronald N, Sand Karina K
Nano-Science Center, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
Biological Nanostructures Facility, The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California, United States.
Cryst Growth Des. 2020 Jun 3;20(6):3762-3771. doi: 10.1021/acs.cgd.0c00029. Epub 2020 Apr 24.
The production of novel composite materials, assembled using biomimetic polymers known as peptoids (N-substituted glycines) to nucleate CaCO, can open new pathways for advanced material design. However, a better understanding of the heterogeneous CaCO nucleation process is a necessary first step. We determined the thermodynamic and kinetic parameters for calcite nucleation on self-assembled monolayers (SAMs) of nanosheet-forming peptoid polymers and simpler, alkanethiol analogues. We used nucleation rate studies to determine the net interfacial free energy ( ) for the peptoid-calcite interface and for SAMs terminated with carboxyl headgroups, amine headgroups, or a mix of the two. We compared the results with determined from dynamic force spectroscopy (DFS) and from density functional theory (DFT), using COSMO-RS simulations. Calcite nucleation has a lower thermodynamic barrier on the peptoid surface than on carboxyl and amine SAMs. From the relationship between nucleation rate ( ) and saturation state, we found that under low-saturation conditions, i.e. <3.3 (pH 9.0), nucleation on the peptoid substrate was faster than that on all of the model surfaces, indicating a thermodynamic drive toward heterogeneous nucleation. When they are taken together, our results indicate that nanosheet-forming peptoid monolayers can serve as an organic template for CaCO polymorph growth.
使用被称为类肽（N-取代甘氨酸）的仿生聚合物组装而成以促使碳酸钙成核的新型复合材料的生产，可为先进材料设计开辟新途径。然而，更好地理解非均相碳酸钙成核过程是必要的第一步。我们确定了在形成纳米片的类肽聚合物和更简单的链烷硫醇类似物的自组装单分子层（SAMs）上进行方解石成核的热力学和动力学参数。我们利用成核速率研究来确定类肽 - 方解石界面以及以羧基端基、胺端基或两者混合终止的SAMs的净界面自由能（ ）。我们将结果与通过动态力谱（DFS）和使用COSMO - RS模拟的密度泛函理论（DFT）确定的 进行了比较。方解石在类肽表面的成核热力学势垒低于在羧基和胺SAMs上的势垒。从成核速率（ ）与饱和状态之间的关系，我们发现，在低饱和度条件下，即 <3.3（pH 9.0）时，类肽底物上的成核比所有模型表面上的都快，这表明存在朝向非均相成核的热力学驱动力。综合来看，我们的结果表明形成纳米片的类肽单分子层可作为碳酸钙多晶型生长的有机模板。
