11 research outputs found
Reconfigurable Droplet–Droplet Communication Mediated by Photochemical Marangoni Flows
Droplets are attractive
building blocks for dynamic matter
that
organizes into adaptive structures. Communication among collectively
operating droplets opens untapped potential in settings that vary
from sensing, optics, protocells, computing, or adaptive matter. Inspired
by the transmission of signals among decentralized units in slime
mold Physarum polycephalum, we introduce
a combination of surfactants, self-assembly, and photochemistry to
establish chemical signal transfer among droplets. To connect droplets
that float at an air–water interface, surfactant triethylene
glycol monododecylether (C12E3) is used for
its ability to self-assemble into wires called myelins. We show how
the trajectory of these myelins can be directed toward selected photoactive
droplets upon UV exposure. To this end, we developed a strategy for
photocontrolled Marangoni flow, which comprises (1) the liquid crystalline
coating formed at the surface of an oleic acid/sodium oleate (OA/NaO)
droplet when in contact with water, (2) a photoacid generator that
protonates sodium oleate upon UV exposure and therefore disintegrates
the coating, and (3) the surface tension gradient that is generated
upon depletion of the surfactant from the air–water interface
by the uncoated droplet. Therefore, localized UV exposure of selected
OA/NaO droplets results in attraction of the myelins such that they
establish reconfigurable connections that self-organize among the
C12E3 and OA/NaO droplets. As an example of
communication, we demonstrate how the myelins transfer fluorescent
dyes, which are selectively delivered in the droplet interior upon
photochemical regulation of the liquid crystalline coating
Reconfigurable Droplet–Droplet Communication Mediated by Photochemical Marangoni Flows
Droplets are attractive
building blocks for dynamic matter
that
organizes into adaptive structures. Communication among collectively
operating droplets opens untapped potential in settings that vary
from sensing, optics, protocells, computing, or adaptive matter. Inspired
by the transmission of signals among decentralized units in slime
mold Physarum polycephalum, we introduce
a combination of surfactants, self-assembly, and photochemistry to
establish chemical signal transfer among droplets. To connect droplets
that float at an air–water interface, surfactant triethylene
glycol monododecylether (C12E3) is used for
its ability to self-assemble into wires called myelins. We show how
the trajectory of these myelins can be directed toward selected photoactive
droplets upon UV exposure. To this end, we developed a strategy for
photocontrolled Marangoni flow, which comprises (1) the liquid crystalline
coating formed at the surface of an oleic acid/sodium oleate (OA/NaO)
droplet when in contact with water, (2) a photoacid generator that
protonates sodium oleate upon UV exposure and therefore disintegrates
the coating, and (3) the surface tension gradient that is generated
upon depletion of the surfactant from the air–water interface
by the uncoated droplet. Therefore, localized UV exposure of selected
OA/NaO droplets results in attraction of the myelins such that they
establish reconfigurable connections that self-organize among the
C12E3 and OA/NaO droplets. As an example of
communication, we demonstrate how the myelins transfer fluorescent
dyes, which are selectively delivered in the droplet interior upon
photochemical regulation of the liquid crystalline coating
Reconfigurable Droplet–Droplet Communication Mediated by Photochemical Marangoni Flows
Droplets are attractive
building blocks for dynamic matter
that
organizes into adaptive structures. Communication among collectively
operating droplets opens untapped potential in settings that vary
from sensing, optics, protocells, computing, or adaptive matter. Inspired
by the transmission of signals among decentralized units in slime
mold Physarum polycephalum, we introduce
a combination of surfactants, self-assembly, and photochemistry to
establish chemical signal transfer among droplets. To connect droplets
that float at an air–water interface, surfactant triethylene
glycol monododecylether (C12E3) is used for
its ability to self-assemble into wires called myelins. We show how
the trajectory of these myelins can be directed toward selected photoactive
droplets upon UV exposure. To this end, we developed a strategy for
photocontrolled Marangoni flow, which comprises (1) the liquid crystalline
coating formed at the surface of an oleic acid/sodium oleate (OA/NaO)
droplet when in contact with water, (2) a photoacid generator that
protonates sodium oleate upon UV exposure and therefore disintegrates
the coating, and (3) the surface tension gradient that is generated
upon depletion of the surfactant from the air–water interface
by the uncoated droplet. Therefore, localized UV exposure of selected
OA/NaO droplets results in attraction of the myelins such that they
establish reconfigurable connections that self-organize among the
C12E3 and OA/NaO droplets. As an example of
communication, we demonstrate how the myelins transfer fluorescent
dyes, which are selectively delivered in the droplet interior upon
photochemical regulation of the liquid crystalline coating
Reconfigurable Droplet–Droplet Communication Mediated by Photochemical Marangoni Flows
Droplets are attractive
building blocks for dynamic matter
that
organizes into adaptive structures. Communication among collectively
operating droplets opens untapped potential in settings that vary
from sensing, optics, protocells, computing, or adaptive matter. Inspired
by the transmission of signals among decentralized units in slime
mold Physarum polycephalum, we introduce
a combination of surfactants, self-assembly, and photochemistry to
establish chemical signal transfer among droplets. To connect droplets
that float at an air–water interface, surfactant triethylene
glycol monododecylether (C12E3) is used for
its ability to self-assemble into wires called myelins. We show how
the trajectory of these myelins can be directed toward selected photoactive
droplets upon UV exposure. To this end, we developed a strategy for
photocontrolled Marangoni flow, which comprises (1) the liquid crystalline
coating formed at the surface of an oleic acid/sodium oleate (OA/NaO)
droplet when in contact with water, (2) a photoacid generator that
protonates sodium oleate upon UV exposure and therefore disintegrates
the coating, and (3) the surface tension gradient that is generated
upon depletion of the surfactant from the air–water interface
by the uncoated droplet. Therefore, localized UV exposure of selected
OA/NaO droplets results in attraction of the myelins such that they
establish reconfigurable connections that self-organize among the
C12E3 and OA/NaO droplets. As an example of
communication, we demonstrate how the myelins transfer fluorescent
dyes, which are selectively delivered in the droplet interior upon
photochemical regulation of the liquid crystalline coating
Reconfigurable Droplet–Droplet Communication Mediated by Photochemical Marangoni Flows
Droplets are attractive
building blocks for dynamic matter
that
organizes into adaptive structures. Communication among collectively
operating droplets opens untapped potential in settings that vary
from sensing, optics, protocells, computing, or adaptive matter. Inspired
by the transmission of signals among decentralized units in slime
mold Physarum polycephalum, we introduce
a combination of surfactants, self-assembly, and photochemistry to
establish chemical signal transfer among droplets. To connect droplets
that float at an air–water interface, surfactant triethylene
glycol monododecylether (C12E3) is used for
its ability to self-assemble into wires called myelins. We show how
the trajectory of these myelins can be directed toward selected photoactive
droplets upon UV exposure. To this end, we developed a strategy for
photocontrolled Marangoni flow, which comprises (1) the liquid crystalline
coating formed at the surface of an oleic acid/sodium oleate (OA/NaO)
droplet when in contact with water, (2) a photoacid generator that
protonates sodium oleate upon UV exposure and therefore disintegrates
the coating, and (3) the surface tension gradient that is generated
upon depletion of the surfactant from the air–water interface
by the uncoated droplet. Therefore, localized UV exposure of selected
OA/NaO droplets results in attraction of the myelins such that they
establish reconfigurable connections that self-organize among the
C12E3 and OA/NaO droplets. As an example of
communication, we demonstrate how the myelins transfer fluorescent
dyes, which are selectively delivered in the droplet interior upon
photochemical regulation of the liquid crystalline coating
Reconfigurable Droplet–Droplet Communication Mediated by Photochemical Marangoni Flows
Droplets are attractive
building blocks for dynamic matter
that
organizes into adaptive structures. Communication among collectively
operating droplets opens untapped potential in settings that vary
from sensing, optics, protocells, computing, or adaptive matter. Inspired
by the transmission of signals among decentralized units in slime
mold Physarum polycephalum, we introduce
a combination of surfactants, self-assembly, and photochemistry to
establish chemical signal transfer among droplets. To connect droplets
that float at an air–water interface, surfactant triethylene
glycol monododecylether (C12E3) is used for
its ability to self-assemble into wires called myelins. We show how
the trajectory of these myelins can be directed toward selected photoactive
droplets upon UV exposure. To this end, we developed a strategy for
photocontrolled Marangoni flow, which comprises (1) the liquid crystalline
coating formed at the surface of an oleic acid/sodium oleate (OA/NaO)
droplet when in contact with water, (2) a photoacid generator that
protonates sodium oleate upon UV exposure and therefore disintegrates
the coating, and (3) the surface tension gradient that is generated
upon depletion of the surfactant from the air–water interface
by the uncoated droplet. Therefore, localized UV exposure of selected
OA/NaO droplets results in attraction of the myelins such that they
establish reconfigurable connections that self-organize among the
C12E3 and OA/NaO droplets. As an example of
communication, we demonstrate how the myelins transfer fluorescent
dyes, which are selectively delivered in the droplet interior upon
photochemical regulation of the liquid crystalline coating
Reconfigurable Droplet–Droplet Communication Mediated by Photochemical Marangoni Flows
Droplets are attractive
building blocks for dynamic matter
that
organizes into adaptive structures. Communication among collectively
operating droplets opens untapped potential in settings that vary
from sensing, optics, protocells, computing, or adaptive matter. Inspired
by the transmission of signals among decentralized units in slime
mold Physarum polycephalum, we introduce
a combination of surfactants, self-assembly, and photochemistry to
establish chemical signal transfer among droplets. To connect droplets
that float at an air–water interface, surfactant triethylene
glycol monododecylether (C12E3) is used for
its ability to self-assemble into wires called myelins. We show how
the trajectory of these myelins can be directed toward selected photoactive
droplets upon UV exposure. To this end, we developed a strategy for
photocontrolled Marangoni flow, which comprises (1) the liquid crystalline
coating formed at the surface of an oleic acid/sodium oleate (OA/NaO)
droplet when in contact with water, (2) a photoacid generator that
protonates sodium oleate upon UV exposure and therefore disintegrates
the coating, and (3) the surface tension gradient that is generated
upon depletion of the surfactant from the air–water interface
by the uncoated droplet. Therefore, localized UV exposure of selected
OA/NaO droplets results in attraction of the myelins such that they
establish reconfigurable connections that self-organize among the
C12E3 and OA/NaO droplets. As an example of
communication, we demonstrate how the myelins transfer fluorescent
dyes, which are selectively delivered in the droplet interior upon
photochemical regulation of the liquid crystalline coating
Solvent Clathrate Driven Dynamic Stereomutation of a Supramolecular Polymer with Molecular Pockets
Control over the
helical organization of synthetic supramolecular
systems is intensively pursued to manifest chirality in a wide range
of applications ranging from electron spin filters to artificial enzymes.
Typically, switching the helicity of supramolecular assemblies involves
external stimuli or kinetic traps. However, efforts to achieve helix
reversal under thermodynamic control and to understand the phenomena
at a molecular level are scarce. Here we present a unique example
of helix reversal (stereomutation) under thermodynamic control in
the self-assembly of a coronene bisimide that has a 3,5-dialkoxy substitution
on the imide phenyl groups (<b>CBI-35CH</b>), leading to “molecular
pockets” in the assembly. The stereomutation was observed only
if the CBI monomer possesses molecular pockets. Detailed chiroptical
studies performed in alkane solvents with different molecular structures
reveal that solvent molecules intercalate or form clathrates within
the molecular pockets of <b>CBI-35CH</b> at low temperature
(263 K), thereby triggering the stereomutation. The interplay among
the helical assembly, molecular pockets, and solvent molecules is
further unraveled by explicit solvent molecular dynamics simulations.
Our results demonstrate how the molecular design of self-assembling
building blocks can orchestrate the organization of surrounding solvent
molecules, which in turn dictates the helical organization of the
resulting supramolecular assembly
Pathway-Controlled Aqueous Supramolecular Polymerization via Solvent-Dependent Chain Conformation Effects
Solute–solvent interactions play a critical role
in multiple
fields, including biology, materials science, and (physical) organic,
polymer, and supramolecular chemistry. Within the growing field of
supramolecular polymer science, these interactions have been recognized
as an important driving force for (entropically driven) intermolecular
association, particularly in aqueous media. However, to date, solute–solvent
effects remain poorly understood in the context of complex self-assembly
energy landscapes and pathway complexity. Herein, we unravel the role
of solute–solvent interactions in controlling chain conformation
effects, allowing energy landscape modulation and pathway selection
in aqueous supramolecular polymerization. To this end, we have designed
a series of oligo(phenylene ethynylene) (OPE)-based bolaamphiphilic
Pt(II) complexes OPE2–4 bearing solubilizing
triethylene glycol (TEG) chains of equal length on both molecule ends,
but a different size of the hydrophobic aromatic scaffold. Strikingly,
detailed self-assembly studies in aqueous media disclose a different
tendency of the TEG chains to fold back and enwrap the hydrophobic
molecular component depending on both the size of the core and the
volume fraction of the co-solvent (THF). The relatively small hydrophobic
component of OPE2 can be readily shielded by the TEG
chains, leading to only one aggregation pathway. In contrast, the
decreased capability of the TEG chains to effectively shield larger
hydrophobic cores (OPE3 and OPE4) enables
different types of solvent quality-dependent conformations (extended,
partly back-folded and back-folded), which in turn induce various
controllable aggregation pathways with distinct morphologies and mechanisms.
Our results shed light on previously underappreciated solvent-dependent
chain conformation effects and their role in governing pathway complexity
in aqueous media
Kinetic Analysis as a Tool to Distinguish Pathway Complexity in Molecular Assembly: An Unexpected Outcome of Structures in Competition
While the sensitive dependence of
the functional characteristics
of self-assembled nanofibers on the molecular structure of their building
blocks is well-known, the crucial influence of the dynamics of the
assembly process is often overlooked. For natural protein-based fibrils,
various aggregation mechanisms have been demonstrated, from simple
primary nucleation to secondary nucleation and off-pathway aggregation.
Similar pathway complexity has recently been described in synthetic
supramolecular polymers and has been shown to be intimately linked
to their morphology. We outline a general method to investigate the
consequences of the presence of multiple assembly pathways, and show
how kinetic analysis can be used to distinguish different assembly
mechanisms. We illustrate our combined experimental and theoretical
approach by studying the aggregation of chiral bipyridine-extended
1,3,5-benzenetricarboxamides (<i>BiPy-<b>1</b></i>) in <i>n</i>-butanol as a model system. Our workflow consists
of nonlinear least-squares analysis of steady-state spectroscopic
measurements, which cannot provide conclusive mechanistic information
but yields the equilibrium constants of the self-assembly process
as constraints for subsequent kinetic analysis. Furthermore, kinetic
nucleation-elongation models based on one and two competing pathways
are used to interpret time-dependent spectroscopic measurements acquired
using stop-flow and temperature-jump methods. Thus, we reveal that
the sharp transition observed in the aggregation process of <i>BiPy-<b>1</b></i> cannot be explained by a single cooperative
pathway, but can be described by a competitive two-pathway mechanism.
This work provides a general tool for analyzing supramolecular polymerizations
and establishing energetic landscapes, leading to mechanistic insights
that at first sight may seem unexpected and counterintuitive