The Global Leader In Viscosity For Over 75 Years


Brookfield AMETEK

Personal Hygiene: Mouthwash

Laboratory Viscometer Application Data Sheet


To freshen breath.

Test Equipment:

  • Spring Torque Range: LV
  • Spindle: Enhanced UL Adapter; ULA-EY
  • Accessories: TC-502 Programmable Bath
  • Speed, rpm: 30, 40, 50, 60, 70, 80, 90, 100, 110 and 120 rpm.
  • Temperature: 22C

* While a particular model/version may be used as an example in this method, any current or past model/version from the same series may also be used. Please consult a sales associate to discuss the most current instrumentation and software available.

We used a Brookfield LVDV-III+ Rheometer, with Rheocalc v3.1 software for automated instrument control and data acquisition. The temperature was regulated using an ULA-EY water jacket connected to a TC-502P Refrigerated Programmable Bath. We ran three trials to ensure repeatability. A syringe was used to measure and dispense 16 mL of the substance into the sample chamber. The spindle and chamber were cleaned before each trial, and fresh material was used for each trial. We equilibrated the sample, spindle and chamber for at least three minutes prior to testing. We ran our test in a speed ramp fashion. Using traditional LV speeds like 30 and 60 rpm can make a sufficient test for this type of material. However, since we used a DV-III+ Rheometer we had the capability of running the test at a wide variety of speeds. Representative data from the analyses are shown in Figure 1, below:

Figure 1: Mouthwash at 22C.

Figure 1 shows that the mouthwash is a Newtonian fluid. Newtonian fluids are characterized by a constant viscosity, independent of shear rate. Slight differences in viscosity over our range of shear rates can be accounted for by the 1% tolerance of the instrument.