One of the main reasons why 100% isopropyl alcohol (IPA) is not commonly used is because it coagulates proteins instantly. When IPA comes into contact with proteins, it creates a protein layer that acts as a protective barrier. This layer prevents the other proteins from further coagulation, making it more difficult for the alcohol to effectively sanitize or disinfect the surface.
In contrast, a 70% solution of IPA is often preferred because it allows for a slower evaporation rate. This slower evaporation increases the contact time between the alcohol and the surface, which enhances its ability to kill bacteria and viruses. The longer contact time allows the alcohol to penetrate and disrupt the cell membranes of microorganisms, effectively neutralizing them.
Furthermore, a 70% solution of IPA is considered more effective at killing microorganisms because it can penetrate the cell wall more easily. Pure IPA may evaporate too quickly before it can fully penetrate the microorganism, thereby reducing its effectiveness.
Personal experiences have also shown the benefits of using a 70% solution of IPA over 100%. In situations where I have used 100% IPA, I have observed that it tends to dry out quickly, leaving a sticky residue behind. This residue can be problematic, as it can attract dirt and bacteria, counteracting the sanitizing effects of the alcohol.
On the other hand, when using a 70% solution of IPA, I have noticed that it evaporates at a slower rate, allowing for a more thorough application. The surface remains wet for a longer period, ensuring better contact and disinfection. Additionally, the 70% solution does not leave behind as much residue, resulting in a cleaner and more sanitized surface.
The use of 100% isopropyl alcohol is not recommended due to its ability to coagulate proteins instantly, creating a protective layer that hinders further disinfection. The slower evaporation rate of a 70% solution allows for increased contact time and better penetration of microorganisms, making it more effective for sanitizing surfaces. Personal experiences have also shown that a 70% solution leaves less residue and provides a cleaner result.