Tribological evaluation of condoms: A hypothesis

According to a WHO factsheet, an estimated 225 million women in developing countries would like to delay or stop child birth but are not using any contraceptive method. Contraceptive method apart from family planning can help in reducing the risk of sexually transmitted diseases as well as reducing adolescent pregnancies. There are many contraceptive methods available in the market today, amongst them condom has gained high popularity because of its portability, cost and ease of use. They are also one of the most effective: research indicates that with correct use, failure rates are 2-3%. Most condoms are made of:

  1. Latex: Most used condom material. Can stretch up to 800% its size, which makes it perfect for resisting heat and friction of sex.
  2. Polyurethane: Much thinner than Latex and allows better heat transfer.
  3. Polyisoprene: Used as an alternative by those who are allergic to Latex.
  4. Lambskin: Very durable, thin and good heat transfer properties but unable to protect against viral STDs/STIs.
  5. Nitrile: Newest material generally used in female condoms. Its oil resistant property helps in handling of oil-based lube like vaseline or baby oil without breaking down.
  6. Silicone: Thicker and stronger than latex and provides a better grip.

From the above mentioned list of manufacturing materials, our interest of material is Lambskin. These condoms are falsely named and are actually made from a layer of membrane from inside of a sheep’s intestines called the cecum. In the late 18th century people have been using animal gut like cecum to make condoms. These skin condoms are believed to be improved sensation during vaginal intercourse and amongst high preference amongst men. But there inability to protect against STDs/STIs are the major hurdles in its sale. On the other hand polymer based condoms are easy to manufacture and less expensive but lacks the “feel” factor.

Figure 1. Cecum of sheep
Figure 1. Cecum of sheep

Here Biomimetics can come into play. Biomimetics is the imitation of the models, systems, and elements of nature for the purpose of solving complex human problems. If researchers are able to mimic the surface characteristics such as elasticity, adhesion, texture, strength of animal gut/intestines then theses surface properties can be coupled with current polymer based condoms in the form of a coating or by substituting a material that imparts these specific properties to the original formulation.

Figure 2. A condom made from animal intestine circa 1900
Figure 2. A condom made from animal intestine circa 1900

The friction and wear performance of these modified condoms can be tested with the help of tribology. Tribology is the science of interacting surface in relative motion and of related subjects and practices. Soft tribology entails the measurement of the friction between soft, compliant surfaces (intended to mimic biological surfaces) under a defined load and across a range of sliding speeds. Soft tribology tests can be performed by making a mimicked version/prototype model of penis-vagina biointerface. Also these tests can be conducted with dry or wet contact (with or without personal lubricants).

In case of lubricated interface, rheology studies have to be conducted on the lubricants for a detailed insight into their viscosity and viscosity index properties. Research have been carried out on developing self-lubricating condoms. Polymers used to manufacture condoms can be embedded with microscopically distributed solid lubricants (graphene and hydrogel materials) which forms a lubricant film at the interface. The films are not present initially and activation depends on extent of wear or dryness at the penis-vagina biointerface. Tribological tests can be carried out in order to understand characteristics of these films at higher interface temperatures and film properties of different solid lubricants.

Researchers associated with field of Biomimetics, Tribology and Rheology have to come together in order to revolutionize condom manufacturing .

References:

  1. “Engineering a Biologically Inspired Condom.” — Northwestern Scholars. Kiser, Patrick Franklin (PD/PI). Web. 14 Oct. 2016.
  2. “Five Kinds of Condoms: A Guide for Consumers.” Go Ask Alice! Web. 14 Oct. 2016.
  3. “Spreading The Love: The Surprisingly Varied Rheology and Bio-tribology of Personal Lubricants – Rheology Lab.” Rheology Lab. Web. 14 Oct. 2016.
  4. “Tribology Testing of Sugar-replaced Soft Drinks – Rheology Lab.” Rheology Lab. Web. 14 Oct. 2016.
  5. Figure 1 – http://www.slideshare.net/guest334add/22-digestive-system-2 Slide 25
  6. Figure 2 – https://en.wikipedia.org/wiki/Condom
  7. The condom of the future? Scientists developing latex replacement that self-lubricates, delivers Viagra and feels better than nothing at all, Adam Withnall, http://www.independent.co.uk/news/science/the-condom-of-the-future-scientists-developing-latex-replacement-that-self-lubricates-delivers-10170841.html

HARSHVARDHAN SINGH
About HARSHVARDHAN SINGH 19 Articles
Harshvardhan Singh is an Automotive Engineer and has good experience in lubrication science and experimental tribology. He loves to write about tribology and related fields such as coating technology, surface engineering and others.

3 Comments

  1. A few years ago, the Bill & Melinda Gates Foundation gave grants to develop a graphene-based condom, and another based on collagen. The technology was real and promising. Years later, no products. Why you ask?

    The American FDA! The researchers reported that even with a $1 Million additional grant from the Gates’, it would be wholly insufficient to tackle the arduous FDA approval process.

    So, don’t expect to see any new space-age condoms arriving store shelves in the foreseeable future.

  2. Well I feel tribology tests can be applied to present condoms as well during quality checks.

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