Hexyltrimethoxysilane (HTMS) is an organosilicon compound widely used in the synthesis of hybrid materials due to its ability to impart hydrophobicity and enhance the mechanical properties of silica particles. HTMS can effectively modify the surface of silica particles, making them more compatible with organic solvents and enhancing their dispersibility in non-aqueous media.
Fig. 1 Reaction scheme of the hydrophobic hybrid silica particles.
In this protocol, we describe the one-pot synthesis of submicron hexane-dispersible silica particles using HTMS and tetraethyl orthosilicate (TEOS) as precursors, with diethylamine as the reaction solvent. The process involves ultrasonication to facilitate the formation of hybrid silica particles.
Materials and Reagents
- Tetraethyl orthosilicate (TEOS)
- Hexyltrimethoxysilane (HTMS)
- Diethylamine (150 mL)
- Water (0.46 mol)
- Methyl isobutyl ketone
- Ethanol
Preparation Procedure of Mixed Silica Particles
1) Dissolve a total of 10 mmol of TEOS and HTMS in 150 mL of diethylamine. Adjust the molar ratio of TEOS to HTMS to one of the following: 1:0, 1:0.15, 1:0.2, or 1:0.4.
2) Add 0.46 mol of water to the mixed solution.
3) Ultrasonicate the solution for 30 seconds using a horn-type ultrasonic homogenizer at 750 W and 20 kHz.
4) Conduct the reaction at room temperature (25°C).
5) After ultrasonication, seal the solution and let it sit undisturbed for 24 hours at 25°C to allow the formation of hybrid silica particles.
6) Rinse the obtained silica particles with methyl isobutyl ketone followed by ethanol.
7) Air-dry the ethanol-rinsed particles to obtain the powdery hybrid silica particles.
Fig. 2 One-step preparation protocol for hydrophobic hybrid silica particles.
Characterization Methods for Mixed Silica Particles
Scanning Electron Microscopy (SEM):
Use SEM for submicron-scale observation of the particles.
Dynamic Light Scattering (DLS):
Measure the particle size in the dispersed state using DLS.
Prepare the sample dispersion by dispersing 5.0 mg of air-dried particles in 10 mL of hexane or water using ultrasonication for 5 minutes.
Thermogravimetric and Differential Thermal Analysis (TG-DTA):
Perform TG-DTA on the dried particles in air, with a temperature elevation rate of 10°C/min from 200°C to 550°C.
This protocol outlines the synthesis and characterization of hybrid silica particles using HTMS, providing a reliable method for creating hydrophobic and mechanically robust materials for various applications.
Reference
- One-pot Spontaneous Formation of Submicron Hexane-dispersible Silica Particles with the Aid of Amphiphilic Reaction Solvent. Colloids and Surfaces A: Physicochemical and Engineering Aspects (2018).
