The Life of a Surface Bubble

Surface bubbles are present in many industrial processes and in nature, as well as in carbonated beverages. They have motivated many theoretical, numerical and experimental works. This paper presents the current knowledge on the physics of surface bubbles lifetime and shows the diversity of mechanisms at play that depend on the properties of the bath, the interfaces and the ambient air. In particular, we explore the role of drainage and evaporation on film thinning. We highlight the existence of two different scenarios depending on whether the cap film ruptures at large or small thickness compared to the thickness at which van der Waals interaction come in to play.

The corona of a surface bubble promotes electrochemical reactions

The evolution of gaseous products is a feature common to several electrochemical processes, often resulting in bubbles adhering to the electrode’s surface. Adherent bubbles reduce the electrode active area, and are therefore generally treated as electrochemically inert entities. Here, we show that this general assumption does not hold for gas bubbles masking anodes operating in water. By means of imaging electrochemiluminescent systems, and by studying the anisotropy of polymer growth around bubbles, we demonstrate that gas cavities adhering to an electrode surface initiate the oxidation of water-soluble species more effectively than electrode areas free of bubbles. The corona of a bubble accumulates hydroxide anions, unbalanced by cations, a phenomenon which causes the oxidation of hydroxide ions to hydroxyl radicals to occur at potentials at least 0.7 V below redox tabled values. The downhill shift of the hydroxide oxidation at the corona of the bubble is likely to be a general mechanism involved in the initiation of heterogeneous electrochemical reactions in water, and could be harnessed in chemical synthesis.

Biocompatible Direct Deposition of Functionalized Nanoparticles using Shrinking Surface Plasmonic Bubble

<p>Functionalized nanoparticles (NPs) are the foundation of diverse applications, such as photonics, composites, energy conversion, and especially biosensors. In many biosensing applications, concentrating the higher density of NPs in the smaller spot without deteriorating biofunctions is usually an inevitable step to improve the detection limit, which remains to be a challenge. In this work, we demonstrate biocompatible deposition of functionalized NPs to an optically transparent surface using shrinking surface plasmonic bubbles. Leveraging the shrinking bubble can enable to mitigate any potential biomolecules degradation by strong photothermal effect, which has been a big obstacle of bridging plasmonic bubbles with biomolecules. The deposited NPs are closely packed in a micro-sized spot (as small as 3 μm), and the functional molecules are able to survive the process as verified by their strong fluorescence signals. We elucidate that the contracting contact line of the shrinking bubble forces the NPs captured by the contact line to a highly concentrated island. Such a shrinking surface bubble deposition (SSBD) is low temperature in nature as no heat is added during the process. Using a hairpin DNA-functionalized gold NP suspension as a model system, SSBD is shown to enable much stronger fluorescence signal compared to the optical pressure deposition and the conventional steady thermal bubble contact line deposition. The demonstrated SSBD technique capable of directly depositing functionalized NPs may benefit a wide range of applications, such as the manufacturing of multiplex biosensors.</p>

Biocompatible Direct Deposition of Functionalized Nanoparticles using Shrinking Surface Plasmonic Bubble

<p>Functionalized nanoparticles (NPs) are the foundation of diverse applications, such as photonics, composites, energy conversion, and especially biosensors. In many biosensing applications, concentrating the higher density of NPs in the smaller spot without deteriorating biofunctions is usually an inevitable step to improve the detection limit, which remains to be a challenge. In this work, we demonstrate biocompatible deposition of functionalized NPs to an optically transparent surface using shrinking surface plasmonic bubbles. Leveraging the shrinking bubble can enable to mitigate any potential biomolecules degradation by strong photothermal effect, which has been a big obstacle of bridging plasmonic bubbles with biomolecules. The deposited NPs are closely packed in a micro-sized spot (as small as 3 μm), and the functional molecules are able to survive the process as verified by their strong fluorescence signals. We elucidate that the contracting contact line of the shrinking bubble forces the NPs captured by the contact line to a highly concentrated island. Such a shrinking surface bubble deposition (SSBD) is low temperature in nature as no heat is added during the process. Using a hairpin DNA-functionalized gold NP suspension as a model system, SSBD is shown to enable much stronger fluorescence signal compared to the optical pressure deposition and the conventional steady thermal bubble contact line deposition. The demonstrated SSBD technique capable of directly depositing functionalized NPs may benefit a wide range of applications, such as the manufacturing of multiplex biosensors.</p>