Roys Joshua S, O'Brien Jennifer M, Stucchi Nicholas D, Raj Gaurav, Hill Adam D, Ye Jingyun, Brown Ryan D
Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY, 13699, USA.
Department of Chemistry, St. Lawrence University, Canton, NY, 13617, USA.
Small. 2022 Nov;18(46):e2204152. doi: 10.1002/smll.202204152. Epub 2022 Oct 10.
The polymerization of 1,4-benzenediboronic acid (BDBA) on mica to form a covalent organic framework (COF-1) reveals a dramatic increase in crystallinity when physically confined by exfoliated graphene. COF-1 domains formed under graphene confinement are highly geometric in shape and on the order of square micrometers in size, while outside of the exfoliated flakes, the COF-1 does not exhibit long-range mesoscale structural order, according to atomic force microscopy imaging. Micro-Fourier transform infrared spectroscopy confirms the presence of COF-1 both outside and underneath the exfoliated graphene flakes, and density functional theory calculations predict that higher mobility and self-assembly are not causes of this higher degree of crystallinity for the confined COF-1 domains. The most likely origin of the confined COF-1's substantial increase in crystallinity is from enhanced dynamic covalent crystallization due to the water confined beneath the graphene flake.
1,4-苯二硼酸（BDBA）在云母上聚合形成共价有机框架（COF-1），研究发现，当被剥离的石墨烯物理限制时，其结晶度会显著提高。根据原子力显微镜成像结果，在石墨烯限制下形成的COF-1域形状高度规则，尺寸约为平方微米级，而在剥离薄片之外，COF-1没有呈现出长程介观结构有序性。显微傅里叶变换红外光谱证实了在剥离的石墨烯薄片外部和下方均存在COF-1，密度泛函理论计算预测，较高的迁移率和自组装并非受限COF-1域结晶度更高的原因。受限COF-1结晶度大幅提高的最可能原因是石墨烯薄片下方受限的水导致动态共价结晶增强。
