## Abstract

We have studied the shear relaxation of heneicosanoic ([Formula Presented]) acid monolayers on the surface of water at different temperatures and pressures, in the CS, [Formula Presented], [Formula Presented], and S phases. A torsion pendulum was displaced from its equilibrium position by an angle θ(0) and the relaxation θ(t) was measured. Only the CS phase sustains a static shear (∼160 dyn/cm) at the time scales studied (≊[Formula Presented] s). The data fit well to a stretched exponential form θ(t)=θ(∞)+θ(0)-θ(∞)exp-(t/τ[Formula Presented]. We find that k[Formula Presented]/n is independent of the torsion constant k; this implies that the viscosity is time dependent. k[Formula Presented]/n is a strong function of pressure and temperature. At phase boundaries there is a discontinuity in either k[Formula Presented]/n or its slope.

Original language | English (US) |
---|---|

Pages (from-to) | 1770-1773 |

Number of pages | 4 |

Journal | Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics |

Volume | 54 |

Issue number | 2 |

DOIs | |

State | Published - 1996 |

## ASJC Scopus subject areas

- Statistical and Nonlinear Physics
- Statistics and Probability
- Condensed Matter Physics