Mesomorphic Character of Quaternary Ammonium Salts Affected by Secondary Hydrogen Bonding Interactions

Abstract

In the present study we investigate the effect of hydrogen bonding secondary interactions on the crystalline and liquid crystalline phases of quaternary ammonium salts functionalized by a hydroxyl or a carboxylic group attached at the polar head through an appropriate spacer. The observed liquid crystalline phases have resulted from the interplay of the effects of the long aliphatic chain, n= 12, 14, 16, 18, the length of the spacer m= 1, 3, 4, 5, 6 and certainly of hydrogen bonding interactions. The smectic liquid character of these quaternaries was established by optical microscopy, differential scanning calorimetry and X-ray diffraction studies.

Key Words:

• Amphiphilic quaternary ammonium salts
• smectic liquid crystalline phases
• X-ray diffraction
• thermal analysis