The effect of different arms on the properties of chiral branched-arm liquid crystals based on isosorbide as the chiral core

A new series of two-arm(MA(1), MA(2)), four-arm(MA(3)) and six-arm(MA(4)) chiral liquid crystalline compounds containing isosorbide as the chiral core were synthesised. Four precursors of branched-arm A(1)-A(4) were first obtained, and then were esterised separately with isosorbide to obtain four chiral branched-arm liquid crystals (MA(1)-MA(4)). The structure and properties have been characterised. The results show that MA(1) was smectic-cholesteric phase with a fan-like and oily streak texture; MA(2)-MA(4) showed a cholesteric phase with oily streak texture, or lined texture and finger print texture. Isosorbide successfully induced a cholesteric phase. The melting point and clearing point values for MA(1)-MA(4) first increased and then decreased. The branched-arm and chiral core quantity affected the liquid crystalline properties. At the same time, the difference in side-arms resulted in different directions of rotation. MA(1)-MA(2) showed right-handed rotation and had selective reflection; MA(3)-MA(4) demonstrated left-handed rotation and did not have selective reflection.