Analysis of dip coating processing parameters by double optical monitoring

Abstract

Double optical monitoring is applied to determine the influence of main process parameters on the formation of sulfated zirconia and self-assembled mesoporous silica solgel films by dip coating. In addition, we analyze, for the first time to the best of our knowledge, the influence of withdrawal speed, temperature, and relative humidity on refractive-index and physical thickness variations (uncertainties of Ϯ0.005 and Ϯ7 nm) during the process. Results provide insight into controlled production of single and multilayer films from complex fluids by dip coating.

Sulfated Zirconia Synthesized in a One Step Solvent-Free Method for Removal of Olefins from Aromatics

“…17,18 The traditional synthesis method to prepare sulfated zirconia is an impregnation− immersion one, which dips zirconium hydroxide into ammonia sulfate or sulfuric acid followed by calcination at 650 °C. 19 The most common raw material resource of Zr is zirconium oxychloride (ZrOCl 2 •8H 2 O), which can be transferred into zirconium hydroxide (Zr(OH) 4 ) in mixing with ammonium hydroxide (NH 3 •H 2 O), while raw Zr in nature is in the form of azurite which includes ZrSiO 3 instead of ZrOCl 2 •8H 2 O. The industrial process for ZrOCl 2 •8H 2 O purification can be simplified as the following chemical equations:…”

“…Recently, sulfated zirconia (SZ) has also shown excellent performance toward olefin removal in aromatics . Due to its properties of superior acidity, sulfated zirconia is widely used in alkylation, , isomerization, , acylation, , condensation, , and esterification reactions. , Zirconium oxide (ZrO 2 ) possesses both acid sites and base sites and can convert to solid acid by supporting SO 4 2– in the inductive effect promoting by SO bonds. , The traditional synthesis method to prepare sulfated zirconia is an impregnation–immersion one, which dips zirconium hydroxide into ammonia sulfate or sulfuric acid followed by calcination at 650 °C . The most common raw material resource of Zr is zirconium oxychloride (ZrOCl 2 ·8H 2 O), which can be transferred into zirconium hydroxide (Zr­(OH) 4 ) in mixing with ammonium hydroxide (NH 3 ·H 2 O), while raw Zr in nature is in the form of azurite which includes ZrSiO 3 instead of ZrOCl 2 ·8H 2 O.…”