Slime, a popular plaything, is a unique material known for its stretchy and gooey texture. It behaves as a non-Newtonian fluid, meaning its viscosity changes depending on the force applied to it, acting sometimes like a liquid and other times like a solid. Most common types of slime are not truly water-soluble; they do not dissolve uniformly. Instead, water can affect slime in various ways, altering its consistency and appearance rather than making it disappear.
The Chemistry of Slime and Water
The properties of typical homemade slime stem from its primary ingredients: polyvinyl alcohol (PVA) glue and an activator, commonly borax. PVA glue consists of long polymer chains dispersed in water. When borax is introduced, it dissolves and forms borate ions, which act as cross-linkers.
These borate ions form weak bonds between the individual PVA polymer chains. This process creates a three-dimensional network that traps water molecules within its structure. Unlike truly water-soluble substances, where individual molecules spread out and mix evenly with water, slime’s cross-linked polymer network prevents its components from fully dissociating. This trapped water gives slime its characteristic texture.
While the formation of these cross-links involves a chemical reaction, the overall transformation of glue into slime is often considered a physical change. This is because the bonds formed are typically weak and reversible, allowing the material to retain its original molecular identity despite altered properties.
How Slime Interacts with Water
Slime does not dissolve in water like sugar or salt. Instead, its unique polymer structure dictates a different set of physical interactions. The water can be absorbed into the slime’s existing polymer network, which often causes the slime to swell and become softer or more pliable.
Excessive exposure to water can dilute the cross-links within the slime, making it appear stickier or more liquid-like. This happens as water molecules interfere with the weak bonds holding the polymer chains, allowing them to slide past each other more easily. If enough water is introduced, the slime may even break apart into smaller, less cohesive pieces.
Slime’s reaction to water varies depending on its original composition. Slimes made with different activators or varying ratios of ingredients may exhibit different degrees of swelling, stickiness, or disintegration when submerged. For instance, some formulations might become more gooey, while others might become more brittle and breakable.
Removing Slime from Surfaces
Cleaning slime from surfaces requires an understanding of its non-soluble nature and its interaction with certain chemicals. First, manually remove as much of the bulk material as possible by picking it up or gently scraping it off. This minimizes the amount of residue needing further treatment.
For residual slime, acidic solutions like white vinegar are effective. The acidity in vinegar helps to break down the adhesive properties of the glue and can weaken the polymer bonds, making the slime easier to remove. Applying a mixture of white vinegar and water, allowing it to soak for several minutes, then scrubbing or blotting the area can lift the slime.
Rubbing alcohol can also dissolve the bonds within the slime structure. However, test it on an inconspicuous area first, as it can potentially damage or discolor certain fabrics and finishes. Alternatively, freezing the slime with ice cubes can make it brittle and easier to scrape off from porous surfaces like carpet or fabric. When cleaning, blotting the affected area is preferable to rubbing, which can spread the stain or push the slime deeper into the material.