Chemical modification/grafting of mesoporous alumina with polydimethylsiloxane (PDMS)

Abstract

A method for polydimethylsiloxane grafting of alumina powders is described which involves chemical modification of the surface of mesoporous (5 nm) γ-alumina flakes with a linker (3-aminopropyltriethoxysilane: APTES), either by a solution phase (SPD) or a vapour phase (VPD) reaction, followed by PDMS grafting. The systems were analysed by FTIR, gas adsorption/desorption and TGA. Grafting is proven by FTIR for all cases, meaning that a covalent bond exists between inorganic particle and organic moiety. It is demonstrated that the way of applying APTES (by SPD or VPD) has an effect on the morphology of linker as well as of PDMS. A more controlled grafting of the APTES linker on γ-alumina is possible by the VPD method, resulting in efficient grafting and good infiltration of PDMS in the pores of the inorganic system. Stability tests on these PDMS grafted alumina show no degradation after 14 days soaking in a wide range of solvents. Surface modification of metal oxide particles by organic moieties via a chemical reaction can adapt its interfacial properties and renders a high chemical stability of these inorganic-organic hybrids. This validates the use of these materials under severe applications like in membranes for solvent nanofiltration or for protein immobilization and resin modification in e.g. chromatographic applications.

Preparation of alumina membranes comprising a thin separation layer and a support with straight open pores for water desalination

“…For comparison, a three-layered alumina membrane coded as M2 was prepared from the alumina slurry alone. The as-sintered alumina membranes were ultrasonically cleaned in respectively acetone, ethanol and water for 10 min to remove any impurities and to obtain more hydroxy groups, making the membrane surface better accessible for the grafting reaction [19]. After this cleaning step the membranes were dried in an oven at 100 °C for 2 h, immersed into a 2 wt% FAS ethanol solution at room temperature and left for 24 h to allow the coupling reaction to occur.…”

Combining Rigid Cellulose Nanocrystals and Soft Silk Proteins: Revealing Interactions and Alignment in Shear

“…Proof of chemisorption versus physisorption is a long‐standing question for the silanization platform. [ 64 ] Due to the potential for the introduction of a wide range of novel reactive or “click” functionalities, confirming covalent attachment is critical for the reduction of downstream leaching of the introduced functionalities, from the surface of celluloses.…”

Solution‐based deposition of nano‐embossed metal electrodes on cotton fabrics for wearable heaters and supercapacitors

“…However, the surface‐modified cotton with DETA (DETA‐cotton) could not be used directly because there was a large excess of physisorbed DETA molecules on the surface of cotton, due to hydrogen bonding between the DETA molecules and the hydroxyl groups on the cotton surface after silanization of cotton with DETA. These molecules could not be removed simply by washing with deionized water, which resulted in contamination during the processes that followed 40,41 . Therefore, to remove the physisorbed DETA molecules on the DETA‐cotton, the DETA‐cotton was immersed in diluted formic acid.…”