Squeezing Toothpaste

I am one among those millions of people who squeeze the tube of toothpaste harder and harder towards the end, trying to extract the last nanogram of paste before switching over to a fresh tube. Toothpaste is not the only stuff to be meted out this ignominious punishment in millions of households. There are hundred other gooey things like ketchup and mayonnaise which endure the same fate, as they try to cling like leeches to the inner walls of their containers. While this behaviour begs a serious study by sociologists, it is also a problem that strikes deep at the core of sustainability. Sticky gels, creams and pastes worth hundreds of millions of dollars are discarded every year, still stuck to the insides of their packaging. 

Stuff adhering to the walls of plastic packaging and metal cans also slows down their recycling and makes it more expensive. The problem extends to the equipment and pipelines in which these sticky materials are manufactured and processed. Cleaning chemicals and hundreds of gallons of water are required to expel the clingy stuff at periodic intervals and the resulting effluent also needs to be disposed of safely. So, can something be done to expel all the toothpaste leaving behind a squeaky clean tube?

LiquidGlide, a MIT-based start-up, seems to have solved the problem. The founders of the company have developed a robust superhydrophobic surface that will help all of the toothpaste to glide out of the tube. Inspired by the lotus leaf, the technology creates a liquid impregnated surface with non-wetting properties. Previously, nano-engineered textures have been used to produce hydrophobic surfaces with water-repellent and self-cleaning properties. Superhydrophobic surfaces are created by engineering nanoscale roughness on an intrinsically hydrophobic coating.

Hydrophobicity is the result of air-water interface within the nano-surface textures. The air entrained within the surface textures are displaced by impingement of liquid droplets, thereby diminishing the non-wetting property. LiquidGlide’s innovation lies in overcoming this vulnerability and creating a very robust superhydrophobic surface. The novelty essentially consists of impregnating a liquid within the matrix of the nano-engineered surface topography.

Different types of liquids have been successfully used for impregnating the surface textures. This makes it possible for the technology to be customised for a wide variety of applications. The innovation has implications beyond revolutionising toothpaste and ketchup packaging. It can be used to reduce viscous drag in oil and gas pipelines. It can prevent icing on aircrafts and powerlines. It has the potential to enhance heat transfer in condensers and to improve lubrication in compressors and engines. It will eliminate occlusions in medical devices. Losses during manufacturing can be substantially reduced. 

This innovation is yet another fine example of manipulating material properties through clever engineering to achieve miraculous results. LiquidGlide’s technology has already been lapped up by Colgate. My morning routine of exercising the fingers on the toothpaste tube will have to cease soon