Visualizing Polymer Crystallization in Ultrathin Layers Using a Single-Macromolecule Tracking Method

Bi, Wuguo; Teguh, Jefri S.; Yeow, Edwin K. L.

doi:10.1103/physrevlett.102.048302

Cited by 21 publications

(13 citation statements)

References 21 publications

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“…26 Thin films with fractal morphology have been prepared experimen-tally. For example, metal oxide nanoparticles, 27 blends containing polyaniline or its oligomeric counterpart, 28 polyelectrolyte containing sodium chloride salt, 29 poly(ethylene glycol), 30,31 stereoregular poly(methyl methacrylate), 32 and isotactic polystyrene, 33 form fractal-type structures upon spincasting from their solutions on flat substrates. Upon further examination, the materials that formed fractal features in these studies are either crystalline or semicrystalline.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Upon further examination, the materials that formed fractal features in these studies are either crystalline or semicrystalline. These reports did point out that fractal structure formation is driven by crystallization forces and follows the DLA model. − Most of the reported sample preparations, however, involved spin-casting. There is one report describing fractal structure formation of type I collagen adsorbed on polystyrene after a slow drying process .…”

Section: Introductionmentioning

confidence: 99%

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Unusual Morphologies of Poly(vinyl alcohol) Thin Films Adsorbed on Poly(dimethylsiloxane) Substrates

et al. 2016

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Adsorption of poly(vinyl alcohol) (PVOH), 99% and 88% hydrolyzed poly(vinyl acetate), to poly(dimethylsiloxane) (PDMS) substrates was studied. The substrates were prepared by covalently attaching linear PDMS polymers of 2, 9, 17, 49, and 116 kDa onto silicon wafers. As the PDMS molecular weight/thickness increases, the adsorbed PVOH thin films progressively transition from continuous to discontinuous morphologies, including honeycomb and fractal/droplet. The structures are the result of thin film dewetting that occurs upon exposure to air. The PVOH film thickness does not vary significantly on these PDMS substrates, implicating the PDMS thickness as the cause for the morphology differences. The adsorbed PVOH thin films are less stable and have a stronger tendency to dewet on thicker, more liquid-like PDMS layers. When PVOH(99%) and PVOH(88%) thin films are compared, fractal and droplet morphologies are observed on high molecular weight PDMS substrates, respectively. The formation of the unique fractal features in the PVOH(99%) thin films as well as other crystalline and semicrystalline thin films is most likely driven by crystallization during the dehydration process in a diffusion-limited aggregation fashion. The only significant enhancement in hydrophilicity via PVOH adsorption was obtained on PDMS(2k), which is completely covered with a PVOH thin film. To mimic the lower receding contact angle and less liquid-like character of the PDMS(2k) substrate, light plasma treatment of the higher molecular weight PDMS substrates was carried out. On the treated PDMS substrates, the adsorbed PVOH thin films are in the more continuous honeycomb morphology, giving rise to significantly enhanced wettability. Furthermore, hydrophobic recovery of the hydrophilized PDMS substrates was not observed during a 1 week period. Thus, light plasma oxidation and subsequent PVOH adsorption can be utilized as a means to effectively hydrophilize conventional PDMS substrates. This study illustrates that the stability and morphology of adsorbed polymer thin films depend on polymer crystallinity as well as substrate physical properties.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Unusual Morphologies of Poly(vinyl alcohol) Thin Films Adsorbed on Poly(dimethylsiloxane) Substrates

et al. 2016

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“…In the following, we concentrate on molecular glass‐forming liquids, where the host molecules are smaller than the probes. The case of polymers is more complex because of the different length scales of monomer and polymer chain, particularly when the probe is also a polymer 19. The different experiments appear to agree as to the extent of the heterogeneity.…”

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confidence: 92%

Towards a Molecular View of Glass Heterogeneity

Orrit

2012

Angew Chem Int Ed

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Curds show the whey: the vexing problem of the glass transition has been frustrating experimentalists and theorists for more than a century. One difficulty is in quantifying the structure of an inhomogeneous system, even when "curds" and "whey" are made out of the same material. To explore the rich space of configurations of these complex systems, a new generation of experiments with a range of different local probes is needed.

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“…The single-molecule/particle tracking technique is a powerful tool to track the motion of single fluorescent molecules/particles and can be achieved via fluorescence wide-field microscopy (WFM). WFM was previously used to study polymer physics (e.g., crystallization of single polymeric chains in thin layers) 54 , dynamics of single swarming bacteria 55 and catalysis 56 . WFM has also been utilized to understand, at the bulk level, materials-related phenomena, such as hole nucleation and growth in polymer blend films 57 , the coffee ring effect 58 , and drugrelease dynamics from antibiotic carriers to tackle bacterial infection 59 .…”

Section: Introductionmentioning

confidence: 99%

Single-particle tracking of the formation of a pseudoequilibrium state prior to charged microgel cluster formation at interfaces

Yeow

2020

NPG Asia Mater

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The correlation between micron-sized particles and their self-assembly at fluid interfaces is important in several applications, including the stabilization of Pickering emulsions and creation of colloidosomes. In this study, through real-time visualization of the diffusion of microgel particles at the air–water interface of an aqueous pendant drop, the formation of a pseudoequilibrium state is observed prior to cluster formation. It is shown here that at the microscopic level, a pendant drop surface has nonuniform principal curvatures and exhibits positive deviatoric curvature (+∆c) gradients. The +∆c gradients confer superdiffusive motion to single ionic microgel particles and are responsible for bringing particles that are initially far apart to common sites on the interface with high curvatures. Prior to two-particle cluster formation, the balance between pairwise repulsion, capillary attraction and +∆c-induced energy that pushes the pair of particles to a high curvature creates a pseudoequilibrium state where the interparticle distance remains relatively invariant for a long period of time. This observation is also noted during higher-order cluster formation. Thereafter, a sufficiently strong long-range attraction potential is activated to facilitate cluster formation. Real-time tracking of the evolution of cluster formation provides useful insights into the interplay between various interactions experienced by ionic microgels.

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Visualizing Polymer Crystallization in Ultrathin Layers Using a Single-Macromolecule Tracking Method

Cited by 21 publications

References 21 publications

Unusual Morphologies of Poly(vinyl alcohol) Thin Films Adsorbed on Poly(dimethylsiloxane) Substrates

Unusual Morphologies of Poly(vinyl alcohol) Thin Films Adsorbed on Poly(dimethylsiloxane) Substrates

Towards a Molecular View of Glass Heterogeneity

Single-particle tracking of the formation of a pseudoequilibrium state prior to charged microgel cluster formation at interfaces

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