PMID- 21230489
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20110426
LR  - 20110114
IS  - 1550-2376 (Electronic)
IS  - 1539-3755 (Linking)
VI  - 82
IP  - 5 Pt 1
DP  - 2010 Nov
TI  - Calorimetric study of the nematic to smectic-A phase transition in 
      octylcyanobiphenyl-hexane binary mixtures.
PG  - 051702
AB  - The continuous nematic to smectic-A (N-SmA) phase transition has been studied by 
      high-resolution ac-calorimetry in binary mixtures of the liquid crystal 
      octylcyanobiphenyl (8CB) and a nonmesogenic, low-molecular weight, solvent 
      n-hexane (hex) as a function of temperature and solvent concentration. Heating 
      and cooling scans about the N-SmA transition temperature were repeatedly 
      performed on pure and six 8CB+hex samples having hexane molar concentration 
      ranging from x(hex)=0.02 to 0.12. All 8CB+hex samples in this range of x(hex) 
      remain macroscopically miscible and exhibit an N-SmA heat capacity peak that 
      shifts nonmonotonically to lower temperature and evolves in shape, with a 
      reproducible hysteresis, as x(hex) increases. The imaginary part of heat capacity 
      remains zero up to x(hex)(TCP)  approximately  0.07 above which the distinct peak is observed, 
      corresponding to a jump in both the real and imaginary enthalpy, indicating the 
      onset of first-order behavior. A simple power-law analysis reveals an effective 
      exponent that increases smoothly from 0.30 to 0.50 with an amplitude ratio 
      A-/A+-->1 as x(hex)-->x(hex)(TCP). This observed crossover of the N-SmA toward a 
      tricritical point driven by solvent concentration is consistent with previous 
      results and can be understood as a solvent softening of the liquid crystal and 
      concument promoting of nematic fluctuations.
FAU - Sigdel, Krishna P
AU  - Sigdel KP
AD  - Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts 
      01609, USA.
FAU - Iannacchione, Germano S
AU  - Iannacchione GS
LA  - eng
PT  - Journal Article
DEP - 20101111
PL  - United States
TA  - Phys Rev E Stat Nonlin Soft Matter Phys
JT  - Physical review. E, Statistical, nonlinear, and soft matter physics
JID - 101136452
EDAT- 2011/01/15 06:00
MHDA- 2011/01/15 06:01
CRDT- 2011/01/15 06:00
PHST- 2010/07/27 00:00 [received]
PHST- 2011/01/15 06:00 [entrez]
PHST- 2011/01/15 06:00 [pubmed]
PHST- 2011/01/15 06:01 [medline]
AID - 10.1103/PhysRevE.82.051702 [doi]
PST - ppublish
SO  - Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Nov;82(5 Pt 1):051702. doi: 
      10.1103/PhysRevE.82.051702. Epub 2010 Nov 11.