The Basics of Microfluidic Tubings and Sleeves

Please note that if you are more familiar with the metric system, microfluidic tubing dimensions are usually not given in millimeters. Instead, tubing and sleeve measurements make use of the Imperial Unit system, which commonly uses fractions of inches for size values.

Thus, to facilitate the conversion between the two systems, it might be useful for you to refer to this non-exhaustive list of values. If you have the measurement in inches and need to know the millimeters:

 

Microfluidic tubing:
Inches to Millimeters Quick Conversion Guide

In order of increasing size…

1/64 inch = 0.39mm 1/32 inch = 0.79mm 1/16 inch = 1.58mm 1/8 inch = 3.17mm 5/32 inch = 3.96mm 3/16 inch = 4.76mm 1/4 inch = 6.35mm

5/16 inch = 7.93mm 3/8 inch = 9.52mm 1/2 inch = 12.70mm 5/8 inch = 15.87mm 3/4 inch = 19.05mm 7/8 inch = 22.22mm 1 inch = 25.40mm

Microfluidic Tubing: what is a sleeve ?

When your tubing is too small to be used with your fitting, you need to play around with the ID and OD values to find a sleeve that can successfully connect your capillary tubing into the receiving port.

In the following picture, for instance, a green F-247 FEP sleeve, with a 1/16’’ outer diameter, has an appropriate internal diameter for sliding over 1/32’’ tubing. Thus, 1/32’’ tubing can be inserted into this sleeve so that it becomes compatible with fittings designed for 1/16’’ OD tubing, which is the most commonly used outer diameter in microfluidic instrumentation setups. The mounting is secured by the compression applied by the ferrule on the tubing when the fitting is screwed on. We propose a specific kit developed to make life easier for anyone who wants to use 1/32 OD capillary tubing with fittings designed for 1/16’’ OD tubing.

 

Microfluidic Tubings and Sleeves : materials used

Knowing  the material from which certain types of tubing have been manufactured is particularly important for the  quality of the connection you are making.

Let’s be honest: the perfect material doesn’t exist. You will very often have to choose between pressure resistance and chemical resistance. Therefore you should be very careful about to the nature of the reagents that will flow through your tubing. In our microfluidic kits section, we propose a specific section dedicated to microfluidic tubing. Regardless of whether it is a matter of fluid transport, fluidic resistance, or Syringe Pump Flow Stabilizer Microfluidic Kit our selection of tubing will bring you complete satisfaction. They are available for an extremely broad range of applications, from general purpose liquid dispensing to droplet microfluidics and syringe pump improvement.

 Some of the most commonly used tubing materials in microfluidic instrumentation setups are:

• Microfluidic PEEK tubing (Polyetheretherketone): This biocompatible and very chemically compatible material is widely described as the highest performing thermoplastic material currently available because of its remarkable chemical resistance. However, due to a swelling effect, use caution when using methylene chloride, THF, and DMSO. Nevertheless, these qualities make PEEK tubing and capillaries a material of choice in numerous low and high pressure applications.
• Microfluidic PTFE Teflon tubing (Polytetrafluoroethylene, often described as Teflon® tubing): This transparent, chemically inert and non-toxic material features unmatched chemical resistance and a surface that facilitates flow. Due to its high flexibility, PTFE is mostly used in low pressure applications. When used in microfluidic setups, its rigidity can significantly Syringe Pump Flow Stabilizer Microfluidic Kit and lead to an improved reactivity of the system.
• Microfluidic Tygon tubing : The elasticity and high flexibility of Tygon tubing make it fit tightly to glass and metal and also a material of choice for PDMS device connections. It is also very often used with analytical instruments and pressure controllers, peristaltic pumps, vacuum pumps, or flow switch matrices. The high elasticity of Teflon tubing can be employed in a sophisticated manner to Syringe Pump Flow Stabilizer Microfluidic Kit
• Microfluidic FEP tubing (Fluorinated ethylene-propylene): This nice alternative to PTFE tubing exhibits many similar properties such as biocompatibility and a remarkable inertia to most chemicals. This flexible material with very good optical clarity is mostly used for low pressure microfluidics.
• Microfluidic ETFE  tubing (Ethylene tetrafluoroethylene): This material is chemically stronger compared to PTFE, and as such, is highly chemically resistant. Being more rigid than its molecular relative, it is often used in medium pressure applications.
• Microfluidic PP  tubing (Polypropylene) This tubing offers good resistance to many chemical solutions across the full pH range, making it a material of choice for many standard applications.