How To Learn and Have Fun with Poly(Vinyl Alcohol) and White Glue

Abstract

The general behavior of Newtonian, shear-thinning, shear-thickening, thixotropic, negative thixotropic, and viscoelastic fluids is characterized and briefly discussed in terms of existing theoretical models. Whenever possible, examples of these types of fluids taken from everyday life are given for better understanding. This theoretical introduction is the basis for same, simple, and inexpensive laboratory work employing no special glassware and generally done by pairs of students. The work involves the synthesis of two well-known viscoelastic materials displaying unique properties: poly(vinyl alcohol) (PVA) and white glue, a poly(vinyl acetate)-based emulsion. The students are asked to perform a series of representative mechanical tests on both gels and to describe their observations in full detail. In particular, they are expected to recognize and identify the origin of the intriguing behaviors found (elasticity, spinability, self-siphoning effect, die-swell effect, Weissenberg effect). The tests include the preparation of fibers by extrusion, introducing concepts such as water solubility, hydrogen bonding, and glass transition temperature. The long list of questions, which ideally should be answered at the end of the laboratory work, allows the students to apply the new concepts acquired.

Serum markers of chronic dehydration are associated with saliva spinability

“…To establish the reproducibility of the analysis of spinability using the Neva Meter, Gohara et al . (14) used polyvinyl alcohol in water, which is a well‐known viscoelastic solution that displays unique properties (21). There was a significant correlation ( r = 0·55–0·59, P = 0·05) between spinability and viscosity.…”

“…Factors that control mucus spinability are the concentration of mucous glycoproteins, the degree of intermolecular and intramolecular cross-linkings, and the hydration of mucus (19,20). To establish the reproducibility of the analysis of spinability using the Neva Meter, Gohara et al (14) used polyvinyl alcohol in water, which is a well-known viscoelastic solution that displays unique properties (21). There was a significant correlation (r ¼ 0AE55-0AE59, P ¼ 0AE05) between spinability and viscosity.…”

Extremely Stretchable Strain Sensors Based on Conductive Self‐Healing Dynamic Cross‐Links Hydrogels for Human‐Motion Detection

“…The process is particularly effective in forming 3D gel networks. The hydrogen‐bonding between tetrafunctional borate ion and –OH group provides the self‐healing function because the cross‐link is so weak that it is neither resemblance of covalent bond character nor esterification involved . The hydrogen‐bonding can be easily broken and reformed, allowing the hydrogel to self‐heal and reform.…”

Entirely, Intrinsically, and Autonomously Self‐Healable, Highly Transparent, and Superstretchable Triboelectric Nanogenerator for Personal Power Sources and Self‐Powered Electronic Skins

“…After healing at room temperature for 2 min, HTS‐c‐hydrogel was able to sustain a huge strain (>1500% strain). Compared with PVA‐only healable hydrogel, the non‐Newtonian‐behavior HTS‐c‐hydrogel shows higher stretchability and limited shape stability . Time‐dependent microscopy images of a notch on HTS‐c‐hydrogel are shown in Figure f.…”