Autonomous mesoscale positioning emerging from myelin filament self-organization and Marangoni flows

Abstract

Out-of-equilibrium molecular systems hold great promise as dynamic, reconfigurable matter that executes complex tasks autonomously. However, translating molecular scale dynamics into spatiotemporally controlled phenomena emerging at mesoscopic scale remains a challenge—especially if one aims at a design where the system itself maintains gradients that are required to establish spatial differentiation. Here, we demonstrate how surface tension gradients, facilitated by a linear amphiphile molecule, generate Marangoni flows that coordinate the positioning of amphiphile source and drain droplets floating at air-water interfaces. Importantly, at the same time, this amphiphile leads, via buckling instabilities in lamellar systems of said amphiphile, to the assembly of millimeter long filaments that grow from the source droplets and get absorbed at the drain droplets. Thereby, the Marangoni flows and filament organization together sustain the autonomous positioning of interconnected droplet-filament networks at the mesoscale. Our concepts provide potential for the development of non-equilibrium matter with spatiotemporal programmability.

The mesoscale order of nacreous pearls

“…Multiple clocks in nature govern these living animals, such as the 30-d circalunar cycle ( 60 , 61 ), the day–night circadian cycle ( 62 , 63 ), tidal changes ( 64 ), hibernation in the winter ( 65 , 66 ), and aestivation in the summer ( 67 , 68 ). This fluctuating marine environment and the natural time scales of the mollusk are interconnected influences of the nonequilibrium thermodynamical conditions ( 69 – 71 ) of nacre growth and likely explains the observed power-law behavior.…”

The Mesoscale Crystallinity of Nacreous Pearls

“…Multiple clocks in nature govern these living animals such as the 30-day circalunar cycle 50,51 , the day-night circadian cycle 52,53 , tidal changes 54 , hibernation in the winter 55,56 , and aestivation in the summer 57,58 . This fluctuating marine environment and the natural time scales of the mollusk are interconnected influences of the non-equilibrium thermodynamical conditions [59][60][61] of nacre growth and likely explains the observed power law behavior.…”

Self-sustained Marangoni Flows Driven by Chemical Reactions

“…Concentration gradients at interfaces show particular potential for the emergence of complex behavior in solution. Earlier, our group has shown that self-organizing droplet-filament networks can be obtained between a surfactant source and attractive drain droplets, when the Marangoni flows between them are carefully mediated 28 . Furthermore, it has been demonstrated that surface tension gradients can be used to identify the shortest path through a maze 29,30 , offering the possibility to guide passive objects through a complex topology.…”