Complex Fluids Group University of São Paulo, Brazil

1. LYO-BANANA MESOPHASES COMPOSED BY A MIXTURE OF APOLAR SOLVENTS AND BENT-SHAPED MOLECULES Complex Fluids Group University of São Paulo, Brazil O. G. Martins1, Y. Huang2, A. Jákli2, H. Sawade2 e A. M. Figueiredo Neto1 1Instituto de Física, Universidade de São Paulo, Brazil 2Liquid Crystal Institute, Kent State University, USA

2. Molecules with the “form” of BANANA 1925 1996 Complex Fluids Group University of São Paulo, Brazil

3. STRUCTURES Complex Fluids Group University of São Paulo, Brazil

4. B1 phase of the “smectic type” Complex Fluids Group University of São Paulo, Brazil

5. PHASES Bi,with i from 1 to 7 1) With ferroelectric switching B2 (symmetry C2v), smectic B5smectic, with 2D rectangular ordering in the layers Complex Fluids Group University of São Paulo, Brazil 2) 2D ordering B1smectic, with 2D rectangular ordering in the layers B7structure not well determined [probably of the type 1) above]

6. 3) phases with intercalated molecules B6smectic , with tilted molecules Complex Fluids Group University of São Paulo, Brazil 4) Crystalline phases B3and B4

7. Complex Fluids Group University of São Paulo, Brazil xilene molecular mass: 108

8. B7 phase in the temperature range from 90 to 133oC Smectic with spacing layer of 38.5Å, and a complex in-layer structure. Helical filaments at the transition from the ISO phase. -“telephone-wire-like” texture Complex Fluids Group University of São Paulo, Brazil

9. Complex Fluids Group University of São Paulo, Brazil xilene weaken the dipole- dipole interaction

10. In São Paulo and Kent C10H21 named C10 C14H29named C14 Complex Fluids Group University of São Paulo, Brazil CrB2ISO 68oC 127oC C14 118oC 140oC C10

11. The solvent n – hexadecane: CH3 – (CH2)14 - CH3 boiling point: 287oC density: 0.77g/cm3 molecular weight:226.4 Complex Fluids Group University of São Paulo, Brazil Doping (in weight %): 20 and 40

12. X Ray Diffraction Crystalline phase C10 ,T=22oC d C14 ,T=23oC Complex Fluids Group University of São Paulo, Brazil b 4.4 Å 51.4 Å

13. C14 ,T=23oC, 20wt% B3 phase, oriented d = 54.7Å > d0 wt% b = 4.6Å  b0 wt% Complex Fluids Group University of São Paulo, Brazil hexadecane

14. C14 ,T=79oC, 20wt% B3 phase, non oriented d = 55.6Å > d0 wt% b = 4.6Å  b0 wt% Complex Fluids Group University of São Paulo, Brazil

15. C14 ,T=23oC, 40wt% C14 ,T=79oC, 40wt% Complex Fluids Group University of São Paulo, Brazil

16. C14 ,T=80oC, 0wt% B2 phase Complex Fluids Group University of São Paulo, Brazil

17. C14 ,T=25oC, 20wt% B3 phase Complex Fluids Group University of São Paulo, Brazil

18. CONCLUSIONS 1) The doping with 20 and 40 wt % of hexadecane a) stabilized a B3 phase b) destabilized the B2 phase 2) The doping with xilene (p and m) Complex Fluids Group University of São Paulo, Brazil a) Reduced the clearing point b) Reduced the transition enthalpy

19. Complex Fluids Group University of São Paulo, Brazil

20. Complex Fluids Group University of São Paulo, Brazil