Optical monitoring of polymerizations in droplets with high temporal dynamic range

Cavell, Andrew C.; Krasecki, Veronica; Li, Guoping; Sharma, Alpana; Sun, Hao; Thompson, Matthew P.; Forman, Christopher; Guo, Si Yue; Hickman, Riley J.; Parrish, Katherine A.; Aspuru‐Guzik, Alán; Cronin, Leroy; Gianneschi, Nathan C.; Goldsmith, Randall H.

doi:10.1039/c9sc05559b

Cited by 18 publications

(14 citation statements)

References 104 publications

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“…Previous fluorescence microscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) studies clearly establish either physical or chemical changes separately during polymerization reactions as diverse as ROMP and Phillips alkene polymerization but have been limited in providing simultaneous chemical and physical measurements with high spatiotemporal resolution of both parameters. ,− For example, to date, SEM and TEM have informed on polymer morphology after reaction completion but are generally not suitable for in situ imaging of the polymerization reactions due to the need for high vacuum and dry materials. , Liquid cell TEM has recently enabled in situ imaging of polymerization reactions and other related processes (e.g., cross-linking, scission, self-assembly, and micelle formation) of polymer particles in solvents (typically water), by monitoring morphological changes that occur during the reaction. However, this emerging technique has notable shortcomings because the high-energy electron beam can induce changes to the polymers (scission/degradation), and the ability to image in solution and organic solvents is still limited. − AFM has measured the conformational changes of single polymer strands during reaction but has not provided spatial resolution or direct chemical measurement during an ongoing reaction. , Fluorescence microscopy measurements have reported either physical/chemical changes without concurrent measurement of the other or without spatial resolution (e.g., inspiring recent work by Wöll and Goldsmith ,, and separate prior work from our laboratory ,,, ).…”

Section: Introductionmentioning

confidence: 97%

“…19−21 AFM has measured the conformational changes of single polymer strands during reaction but has not provided spatial resolution or direct chemical measurement during an ongoing reaction. 22,23 Fluorescence microscopy measurements have reported either physical/chemical changes without concurrent measurement of the other or without spatial resolution (e.g., inspiring recent work by Woll and Goldsmith 9,24,25 and separate prior work from our laboratory 6,13,15,26 ).…”

Section: ■ Introductionmentioning

confidence: 99%

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Real-Time Polymer Viscosity–Catalytic Activity Relationships on the Microscale

Eivgi

Blum

2022

J. Am. Chem. Soc.

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Polymer growth induces physical changes to catalyst microenvironments. Here, these physical changes are quantified in real time and are found to influence microscale chemical catalysis and the polymerization rate. By developing a method to “peer into” optically transparent living-polymer particles, simultaneous imaging of both viscosity changes and chemical activity was achieved for the first time with high spatiotemporal resolution through a combination of fluorescence intensity microscopy and fluorescence lifetime imaging microscopy techniques. Specifically, an increase in microenvironment viscosity led to a corresponding local decrease in the catalytic molecular ruthenium ring-opening metathesis polymerization rate, plausibly by restricting diffusional access to active catalytic centers. Consistent with this diffusional-access model, these viscosity changes were found to be monomer-dependent, showing larger changes in microenvironment viscosity in cross-linked polydicyclopentadiene compared to non-crosslinked polynorbornene. The sensitivity and high spatial resolution of the imaging technique revealed significant variations in microviscosities between different particles and subparticle regions. These revealed spatial heterogeneities would not be observable through alternative ensemble analytical techniques that provide sample-averaged measurements. The observed spatial heterogeneities provide a physical mechanism for variation in catalytic chemical activity on the microscale that may accumulate and lead to nonhomogeneous polymer properties on the bulk scale.

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Section: Introductionmentioning

confidence: 97%

Section: ■ Introductionmentioning

confidence: 99%

Real-Time Polymer Viscosity–Catalytic Activity Relationships on the Microscale

Eivgi

Blum

2022

J. Am. Chem. Soc.

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“…Recently, bifurcation-based quantum annealing was proposed as an alternative to standard quantum annealing. [37][38][39][40] Adiabatic quantum computing and quantum annealing provide us with a method of solving for the Ising ground state, by evolving a system from the ground state of an accessible problem to that of a more difficult problem. 29,30,41 Although a molecular computer remains a classical device, unable to avail itself of quantum tunneling across barriers in the potential energy surface relating to the problem Hamiltonian, the rationale can still be extended to simulated annealing.…”

Section: Concept Optimization By Simulated Annealingmentioning

confidence: 99%

A molecular computing approach to solving optimization problems via programmable microdroplet arrays

Guo

Friederich

Cao

et al. 2021

Matter

Self Cite

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The search for novel forms of computing to the dominant von Neumann model-based approach is important as it will enable different classes of problems to be solved. Molecular computers are a promising alternative to semiconductor-based computers given their potential biocompatibility and cost advantages. The vast space of chemical reactions makes molecules a tunable, scalable, and energy-efficient computational vehicle. In molecular computers, memory and processing units can be combined into a single, inherently parallelized device. Here, we present a microdroplet array molecular computer to solve combinatorial optimization problems by employing an Ising Hamiltonian to map problems heuristically to droplet-droplet interactions. The droplets represent binary digits and problems are encoded in intra-and inter-droplet reactions. We propose two implementations: first, a hybrid classical-molecular computer that enforces inter-droplet constraints in a classical computer and, second, a purely molecular computer where the problem is entirely pre-programmed in the nearest-neighbor droplet reactions.

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“…It also should be noted that the reaction geometry is analogous to surface-grafted polymer growths, − except for the presence of the pulling force. This magnetic tweezers approach is part of the emerging efforts toward studying polymerization reactions of synthetic polymers at the single-molecule level. ,,− Bayley et al have used single-nanopore electrical recording to monitor single poly(disulfide)s polymerization at single-monomer resolution, but the polymer growth was limited to ∼10 subunits by the nanopore size. , Using single-molecule fluorescence microscopy, Blum et al visualized the incorporation of single fluorescently labeled monomers into synthetic polymer aggregates amid a high concentration of unlabeled monomers, and Goldsmith et al have quantified the initiation kinetics of single organometallic catalysts for metathesis polymerization reactions …”

Section: Introductionmentioning

confidence: 99%

Tuning Single-Polymer Growth via Hydrogen Bonding in Conformational Entanglements

et al. 2022

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Synthetic polymers have widespread applications in daily life and advanced materials applications. Making polymers efficiently and controllably is highly desired, for which modulating intramolecular and intermolecular interactions have been an effective approach. Recent real-time single-polymer growth studies uncovered nonequilibrium conformational entanglements that form stochastically under living polymerization conditions and which appear to plausibly play key roles in controlling the polymerization kinetics and dispersion. Here, using magnetic tweezers measurements, we study the real-time polymerization dynamics of single polynorbornene-based polymers in which we systematically tune the hydrogen-bonding interactions by titrating the OH content in the monomers and the formed polymers during ring opening metathesis polymerization. Using norbornenes with and without a hydroxyl group and a nonreactive monomer analogue, we show that intrachain and intermolecular hydrogen bonding compete, and both alter the microscopic properties of the nonequilibrium entanglements, leading to surprising multiphasic dependences of polymerization dynamics on the polymer’s OH content. We further formulate a simple model to rationalize quantitatively the observed multiphasic behaviors by considering the different scaling relations of intrachain and intermolecular hydrogen bonding on the OH content. These results provide insights into the interconnected roles of intra-/intermolecular interactions, polymer chain conformations, and free monomers in solution in affecting polymerization kinetics and dispersion, and point to new opportunities in manipulating polymerization reactions.

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Optical monitoring of polymerizations in droplets with high temporal dynamic range

Abstract: Two complementary measurements, fluorescence polarization anisotropy and aggregation-induced emission, allow for in situ optical monitoring of polymerization reaction progress in droplets across varying temporal regimes of the reaction.

Cited by 18 publications

References 104 publications

Real-Time Polymer Viscosity–Catalytic Activity Relationships on the Microscale

Real-Time Polymer Viscosity–Catalytic Activity Relationships on the Microscale

A molecular computing approach to solving optimization problems via programmable microdroplet arrays

Tuning Single-Polymer Growth via Hydrogen Bonding in Conformational Entanglements

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