The critical behavior of the dielectric constant in the polar + polar binary liquid mixture nitromethane + 3-pentanol: An unusual sign of its critical amplitude in the one-phase region

摘要

Dielectric constant measurements have been carried out in the one- and two-phase regions near the critical point of the polar + polar binary liquid mixture nitromethane + 3-pentanol. In the two-phase region, evidence for the |t|2β singularity in the coexistence-curve diameter has been detected, thus confirming the novel predictions of complete scaling theory for liquid-liquid criticality. In the one-phase region, an “unusual” negative sign for the amplitude of the |t|1 − α singularity has been encountered for the first time in an upper critical solution temperature type of binary liquid mixture at atmospheric pressure. Mass density measurements have also been carried out to provide additional information related to such experimental finding, which entails an increase of the critical temperature Tc under an electric field. © 2011 American Institute of Physics Article Outline INTRODUCTION EXPERIMENTS Samples and sample preparation Dielectric constant measurements Density measurements ANALYSIS OF DIELECTRIC CONSTANT AND MASS DENSITY DATA IN THE ONE-PHASE REGION The Maxwell-Wagner relaxation The singular behavior of the static dielectric constant close to T c Mass density data in the one-phase region THE DIELECTRIC CONSTANT IN THE TWO-PHASE REGION DISCUSSION OF THE RESULTS IN THE ONE-PHASE REGION SUMMARY AND CONCLUSIONS