MOE Key Laboratory of Cluster Science, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Soft Matter. 2021 May 19;17(19):5025-5033. doi: 10.1039/d1sm00051a.
Similar to the crystal growth process, additives have a strong influence on the dissolution process of crystals. Studies on the dissolution process may shed light on understanding the biomineralization and bioinspired crystallization process. The influence of different kinds of additives including surfactants and polymers on the dissolution process of calcite {104} planes was investigated in detail in this work. The additives can be classified into three kinds according to their influence on the dissolution process of calcite under different concentration windows. The additives show three different kinds of dissolution behaviors with the increase of additive concentrations according to the tomographic variation of the calcite surface after the dissolution process. There are four dissolution modes of calcite while changing the additive concentrations in the solution. Rhombohedral etch pits with [4[combining macron]41] and [481[combining macron]] step edges are formed on the calcite {104} planes after the dissolution process at low additive concentrations (mode I). Calcite micropyramids begin to appear on the calcite surface and the densities of micropyramids increase with the increase of the additive concentrations until they cover the entire calcite surface after the dissolution process at medium additive concentrations (mode II). Instead of micropyramids, large pyramids with [481[combining macron]] and [4[combining macron]41] step edges and a size of about 50 μm form after the dissolution process at high additive concentrations (modes III and IV). We propose that the different anisotropic dissolution behaviors of calcite are strongly related to the concentrations and the adsorption features of the additives on the calcite surface. The additives may act as inhibitors of calcite dissolution, possibly through adsorption on calcite surfaces without preferred adsorption, or adsorption at specific kink sites or step edges. The influence of additives on the oriented dissolution of calcite is generally related to the adsorption density and homogeneity of additives on the calcite substrates.
类似于晶体生长过程，添加剂对晶体的溶解过程有很强的影响。对溶解过程的研究可能有助于理解生物矿化和仿生结晶过程。在这项工作中，详细研究了包括表面活性剂和聚合物在内的不同种类的添加剂对方解石{104}面溶解过程的影响。根据添加剂在不同浓度窗口下方解石溶解过程的影响，可以将添加剂分为三类。根据溶解后方解石表面的断层变化，随着添加剂浓度的增加，添加剂表现出三种不同的溶解行为。改变溶液中添加剂的浓度时，方解石有四种溶解模式。在低添加剂浓度下（模式 I），溶解后在方解石{104}面上形成具有[4[combining macron]41]和[481[combining macron]]台阶边缘的菱形蚀坑。在中添加剂浓度下（模式 II），方解石表面开始出现方解石微金字塔，并且随着添加剂浓度的增加，微金字塔的密度增加，直到溶解后整个方解石表面被覆盖。在高添加剂浓度下（模式 III 和 IV），形成具有[481[combining macron]]和[4[combining macron]41]台阶边缘且尺寸约为 50μm的大金字塔，而不是微金字塔。我们提出，方解石的不同各向异性溶解行为与添加剂的浓度和在方解石表面的吸附特征密切相关。添加剂可能作为方解石溶解的抑制剂，可能通过在方解石表面无优先吸附的情况下吸附，或者在特定的扭结位点或台阶边缘吸附。添加剂对方解石定向溶解的影响通常与添加剂在方解石衬底上的吸附密度和均一性有关。
