Three-Dimensional Visualization for Early-Stage Evolution of Polymer Aging

Abstract

Monitoring the evolution of polymer aging, especially early-stage aging, over both time and dimensionality can provide in-depth insight into aging-induced material invalidation and even disastrous accidents. However, it remains a great challenge because currently available methods for polymer aging only provide statistic results at a macroscopic scale. Herein, we report the first three-dimensional early-stage visualization (ESV) technique of polymer aging by using the fluorophore-bonded boronic acid to specifically target aging-induced hydroxyl groups through the B−O click reaction. This method can identify the initial aging of polypropylene (PP) as early as 20.0 min. In contrast, no signals can be detected by conventional infrared spectroscopy even after 21 days of thermal treatment. More importantly, the three-dimensional evolution for early-stage polymer aging was demonstrated: faster aggression in the horizontal plane (4.1 × 10 −4 s −1 ) than in the vertical direction (2.6 × 10 −9 m s −1 ) for PP films. The approach could undoubtedly provide valuable information in elucidating mechanistic details of polymer aging in threedimensional scale and assessing the utility of advanced antiaging materials.

Real-Time Imaging of Stress in Single Spherulites and Its Relaxation at the Single-Particle Level in Semicrystalline Polymers

“…The fluorescence intensity of CD/SiO 2 particles in the stretched polypropylene film can be quantified as a gray value using Leica Application Suite X software (Figure S11). , As expected, the fluorescence intensity of the CD/SiO 2 particles was also positively correlated with stress. When the stress reached 8.2 MPa, the fluorescence intensity of CD/SiO 2 particles was 5.5 times higher than that in the absence of stress and 1.8 times higher than that of fluorescent CDs (Figure d).…”

Fluorescence Technique Lighting the Particle Migration in Polymers

“…These LDH particles exhibited platelike morphology with the size distributed around 1 μm (Figure S2C). It has been reported that the boric acid group could target hydroxyl groups in the organic sugars or polyol compounds to form a cyclic boronic ester under mild environments. , To this end, 3-(10-phenyl-9-anthracenyl) phenyl boronic acid (DPBA), a blue emissive fluorescent molecule with boronic acid groups (Figure S3), was employed to target the hydroxide groups on the surface of LDHs through the specific B–O reaction. The labeled LDH particles showed the typical fluorescence emission as DPBA molecules (Figure A).…”

100th Anniversary of Macromolecular Science Viewpoint: Enabling Advances in Fluorescence Microscopy Techniques

“…Selective etching or infiltration methods can be used to enhance contrast, − but these can lead to potential sample damage and an inability to study dynamics in situ . As a comparison, fluorescence microscopy uniquely enables specific staining of the species of interest by means of chemistry or physical interactions or using a material’s intrinsic fluorescence emission. , …”

“…54 As a comparison, fluorescence microscopy uniquely enables specific staining of the species of interest by means of chemistry or physical interactions or using a material's intrinsic fluorescence emission. 55,56 Preferential solubility of staining agents into a particular polymer phase can be achieved by hydrogen bonding or other selective interactions. In seminal work, Hell et al were able to visualize the morphologies of block copolymer thin films using STED (Figure 2).…”