A novel nano‐bubble inflation method for determining the viscoelastic properties of ultrathin polymer films

Abstract

We describe a novel experimental technique for measuring the absolute creep compliance of ultrathin polymer films. The method is based on the classical bubble inflation technique for measuring the biaxial creep compliance of films, reduced in size to measure films with thicknesses down to at least 11.3 nm. The method uses the imaging capabilities of the atomic force microscope (AFM) to determine the time evolution of the geometry of nano-bubbles and thus avoids the problems with data interpretation that can arise due to "contact mechanics" issues when the AFM is used as a direct mechanical testing device.

Mechanical responses of a polymer graphene-sheet nano-sandwich

“…Since the present experiments were performed for bubble deflections larger than three times the film thickness (membrane limit [33]), the bubble deformation is dominated by the stretching stress of the membrane and the bending contribution is negligible [16]. In this case, following the analysis methods described previously [14e17], the radius of curvature R of the inflated bubble is calculated by fitting the bubble profile data to the equation of a circle:…”

“…The TTU nano-bubble inflation methods have been described thoroughly in prior works [15,16]. The filter template holding the nano-sandwich was mounted in a custom pressure cell using the adhesive and pressurized dry air was applied below the filter template to inflate the sample films into bubbles, and the AFM was used to measure the bubble profile.…”

Ultrathin Polymer Films: Rubbery Stiffening, Fragility, and Tg Reduction

“…14,17,27,28 The data is the average for four bubbles. When the bubble deflections are larger than 3 times the film thickness-(membrane limit 29 ), the bending contribution is negligible, and the bubble is dominated by the stretching stress.…”

“…This occurs during the film annealing process and has been discussed previously. 26,27 As shown in Figure 5a, the 21 nm thick PEMA bubble continues to grow with time at 50°C, illustrating a creep behavior below the macroscopic T g of 65°C.…”

Effect of microbubbled water on the removal of a biofilm attached to orthodontic appliances — An in vitro study —

“…The size of the microbubbles is generally 10 μm. However, the size in this study was under 1 μm in diameter, indicating that the bubbles may be called "nanobubbles" 21) . S. mutans and C. albicans was used in this study to make biofilms on the orthodontic appliances.…”