Quick liquid packaging: Encasing water silhouettes by three-dimensional polymer membranes

Abstract

One of the most important substances on Earth is water. It is an essential medium for living microorganisms and for many technological and industrial processes. Confining water in an enclosed compartment without manipulating it or by using rigid containers can be very attractive, even more if the container is biocompatible and biodegradable. Here, we propose a water-based bottom-up approach for facile encasing of short-lived water silhouettes by a custom-made adaptive suit. A biocompatible polymer self-assembling with unprecedented degree of freedom over the water surface directly produces a thin membrane. The polymer film could be the external container of a liquid core or a free-standing layer with personalized design. The membranes produced have been characterized in terms of physical properties, morphology and proposed for various applications from nano- to macroscale. The process appears not to harm cells and microorganisms, opening the way to a breakthrough approach for organ-on-chip and lab-in-a-drop experiments.

On-the-Fly Formation of Polymer Film at Water Surface

“…The propulsion of multiple objects during the formation of the polymeric thin film is visibly shown in Supplementary Video S7 . In a case of interest, the polymer film could be collected from the water as a free-standing layer and transferred directly to the device of interest, as shown and characterized in the static configuration [ 32 ].…”

“…Marangoni propulsion micro-robots integrated with a wireless temperature sensor have very recently been used for sensing external temperature, while the micro-robots propel at the water–air interface [ 28 ]. Very recently we demonstrated a new working principle for liquid locomotion and solid manipulation by using a multipurpose platform guided by a pyroelectric platform [ 29 , 30 , 31 , 32 ]. Malkin and coworkers focused on the spreading of a polymer solution at the interface, leading to a transition from a three-dimensional structure to a two-dimensional film [ 33 ]; they investigated the spreading kinetics of multicomponent solutions with different concentrations over a water surface, measuring the two-dimensional rheological properties of the formed film obtained by phase separation [ 34 , 35 ].…”

Magnetic-actuated “capillary container” for versatile three-dimensional fluid interface manipulation

“…As mentioned above, the capillary container can capture and store liquid with a predesigned shape. Actually, it is more important to preserve or freeze-in the shaped liquid interface for protecting and isolating the material of interest (48)(49)(50). In the last part, we used the container to achieve liquid packaging via the interfacial reaction and explore its potential in drug delivery and release applications.…”

Membrane Fouling Phenomena in Microfluidic Systems: From Technical Challenges to Scientific Opportunities

“…As real membranes can be used, these devices overcome the drawbacks of the previous category, allowing the study of the fouling process at a level of complexity closer to reality; nevertheless, cross-sectional observation of the membrane can be more troublesome compared to MMMs. Embedded membrane microfluidic devices can potentially be useful also to assess the performances of the innovative membrane such as complex-shaped, biocompatible and reinforced ones, as microfluidic modules can be designed ad hoc for specific needs [ 57 , 62 , 68 , 69 ].…”