RHEOLOGICAL BEHAVIOR OF LOACH SURFACE MUCUS

Abstract

The rheological behavior of loach surface mucus was investigated in this paper. The steady shear curves of loach surface mucus can be divided into three regions. The initial shear-independent value attained in the low shear horizontal region of such plots is known as the zero shear or Newtonian viscosity (η0),which is called as the first Newtonian region. Subsequent decrease in viscosity with increasing shear rate ( γ) maybe attributed to progressive breakdown of intermolecular network character,which is called as shear thinning phenomenon. With γ increasing further,viscosity of loach surface mucus becomes shear-independent again. This region is the second Newtonian region. The relationship between apparent viscosity ( ηa ) of loach surface mucus and γ can be well described by the Carreau model. The relationship between specific viscosity ( ηsp ) and concentration ( c) follows ηsp ∝ c1. 5,which is in excellent agreement with that of semidilute entangled polyelectrolyte aqueous solution without salt,suggests it is in the semidilute entangled regime. In the tested angle frequency (ω) region,the storage modulus (G′) and the loss modulus (G″) neither changes a lot with ω. G′ G″ suggests the loach surface mucus exhibits more elasticity than viscidity. There is a critical temperature,35℃ ,for loach surface mucus. Below 35℃ ,ηa of loach surface mucus changes little with temperature. Above 35℃ ,the loach surface mucus appears heat-denature and exhibits thoroughly different rheological responses.