Design and synthesis of ZIF-8 and zinc-imidazole nanofilms

Over the last decade significant efforts have been devoted to the synthesis of zeolitic imidazolate framework (ZIF) films. For practical purposes such as membrane separations and chemical sensing the films must be ultrathin and often continuous on a microscopic level. Several approaches have been proposed, with dip coating offering significant advantages over more complex and expensive techniques. However, studies demonstrating nanoscale control of film density, morphology and thickness are lacking. Within the scope of this thesis, the fabrication of thin ZIF-8 and zinc-imidazole (Zn(mIm)) nanofilms is investigated, aiming at a better understanding of the films formation during the facile dip coating process. Significant attention is dedicated to the identification of the optimal synthesis parameters to fabricate ultrathin nanofilms and demonstrate their potential in chemical sensing and membrane separations. The study is divided into three primary areas and include investigation of: (i) crystalline ZIF-8 thin films derived from colloidal solutions; (ii) partially-crystalline pseudopolymorphic Zn(mIm) nanofilms; and (iii) composite Zn(mIm)@polymer nanofilms. In situ spectroscopic ellipsometry is employed in the investigations of films' morphologies and their dynamic response in the vicinity of the guest gas and vapour penetrants. The results show that films' uniformity and thickness is mainly controlled by the withdrawal speed of the support from the solutions, regardless of the dip coating technique utilised. Targeting ultrathin (