Segmental Relaxation Dynamics of the Core and Corona in a Single Dry Micelle

Ren, Weizhao; Wang, Yuping; Chen, Xin; Zuo, Biao; Zhou, Xianjing; Wang, Xinping

doi:10.1021/acs.macromol.7b02237

Cited by 7 publications

(5 citation statements)

References 53 publications

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“…To estimate the particle diameter, D 0 , one needs to account for the effect of tip broadening. 51,52 As a result of tip broadening, the apparent lateral…”

Section: Resultsmentioning

confidence: 99%

Glass transition temperature of single-chain polystyrene particles end-grafted to oxide-coated silicon

Lin

et al. 2020

The Journal of Chemical Physics

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“…To estimate the particle diameter, D 0 , one needs to account for the effect of tip broadening. 51,52 As a result of tip broadening, the apparent lateral…”

Section: Resultsmentioning

confidence: 99%

Glass transition temperature of single-chain polystyrene particles end-grafted to oxide-coated silicon

Lin

et al. 2020

The Journal of Chemical Physics

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“…The drop in the scattering intensity was attributed to the decreased refractive index and the morphological deviation from the original sphere geometry. Both are direct consequences of the enhanced molecular mobility. , During the glass transition, the segments of the polymer chain began to move locally and thus increased the free volume in the PSNS, resulting in the reduced material density as well as the refractive index. For example, existing studies by using Mie spectroscopy revealed that the refractive index of polystyrene beads in rubbery state was smaller than that in glassy state .…”

Section: Results and Discussionmentioning

confidence: 99%

Optical Imaging of the Molecular Mobility of Single Polystyrene Nanospheres

Liu

et al. 2022

J. Am. Chem. Soc.

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An ultrathin surface layer with extraordinary molecular mobility has been discovered and intensively investigated on thin-film polymer materials for decades. However, because of the lack of suitable characterization techniques, it remains largely unexplored whether such a surface mobile layer also exists on individual polymeric nanospheres. Here, we propose a thermal-optical imaging technique to determine the glass transition (T g) and rubber-fluid transition (T f) temperatures of single isolated polystyrene nanospheres (PSNS) in a high-throughput and nonintrusive manner for the first time. Two distinct steps, corresponding to the glass transition and rubber-fluid transition, respectively, were clearly observed in the optical trace of single PSNS during temperature ramping. Because the transition temperature and size of the same individuals were both determined, single nanoparticle measurements revealed the reduced apparent T f and increased T g of single PSNS on the gold substrate with a decreasing radius from 130 to 70 nm. Further experiments revealed that the substrate effect played an important role in the increased T g. More importantly, a gradual decrease in the optical signal was detected prior to the glass transition, which was consistent with a surface layer with enhanced molecular mobility. Quantitative analysis further revealed the thickness of this layer to be ∼8 nm. This work not only uncovered the existence and thickness of a surface mobile layer in single isolated nanospheres but also demonstrated a general bottom-up strategy to investigate the structure–property relationship of polymeric nanomaterials by correlating the thermal property (T g and T f) and structural features (size) at single nanoparticle level.

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“…The thickness of the adsorbed layer was determined by fitting the refractive index measured above to prevent inaccuracy in the measurement of the adsorbed layer thickness caused by the variation of refractive indices (compared to the bulk polymer) on various systems. Atomic force microscopy (AFM, MultiMode-8, Bruker, Billerica, MA, USA) 7,58–60 was adopted to observe the surface morphology of the adsorbed layer. X-ray reflection (XR) was utilized to determine the density distribution of the adsorbed layer.…”

Section: Methodsmentioning

confidence: 99%