The Intriguing Flow Behavior of Soft Materials

TL;DR

This paper explores the complex flow behaviors of soft materials like colloidal suspensions, emulsions, pastes, granular media, and polymer gels, highlighting their unique rheological properties and underlying mechanisms.

Contribution

It provides an overview of the intriguing flow properties of various soft materials, explaining their complex behaviors and recent insights into their rheology.

Findings

Soft materials exhibit shear-thinning and shear-thickening behaviors.

They display non-zero normal and yield stresses.

Rich deformation behaviors are characterized by unique rheological properties.

Abstract

Materials that can be deformed by thermal stresses at room temperature are called soft materials. Colloidal suspensions comprising solid particles evenly distributed in a fluid phase (smoke, fog, ink and milk, for example), emulsions(mayonnaise, lotions and creams), pastes (tomato ketchup, toothpaste), granular media (a bag of rice or sand), and polymer gels (polysaccharide gels) can be categorized as soft materials and are ubiquitous both at home and in industrial setups. Soft materials exhibit rich flow and deformation behaviors characterized by intriguing properties such as shear-thinning or thixotropy, shear-thickening or dilatancy, non-zero normal and yield stresses, etc. This article explains some of the mysterious flow properties of soft materials.