scholarly journals On the Segmental Dynamics and the Glass Transition Behavior of Poly(2-vinylpyridine) in One- and Two-Dimensional Nanometric Confinement

Author(s):  
Roksana Winkler ◽  
Aparna Beena Unni ◽  
Wenkang Tu ◽  
Katarzyna Chat ◽  
Karolina Adrjanowicz
2009 ◽  
Vol 98 (2) ◽  
pp. 533-537 ◽  
Author(s):  
Yanni Qi ◽  
Jian Zhang ◽  
Shujun Qiu ◽  
Lixian Sun ◽  
Fen Xu ◽  
...  

2021 ◽  
Author(s):  
Shuto Mikajiri ◽  
Tomochika Sogabe ◽  
Ruodan Cao ◽  
Takahiro Kikawada ◽  
Toru Suzuki ◽  
...  

2021 ◽  
Vol 38 (10) ◽  
pp. 106101
Author(s):  
Xiaoyan Sun ◽  
Huaguang Wang ◽  
Hao Feng ◽  
Zexin Zhang ◽  
Yuqiang Ma

Identification of the glass formation process in various conditions is of importance for fundamental understanding of the mechanism of glass transitions as well as for developments and applications of glassy materials. We investigate the role of pinning in driving the transformation of crystal into glass in two-dimensional colloidal suspensions of monodisperse microspheres. The pinning is produced by immobilizing a fraction of microspheres on the substrate of sample cells where the mobile microspheres sediment. Structurally, the crystal-hexatic-glass transition occurs with increasing the number fraction of pinning ρ pinning, and the orientational correlation exhibits a change from quasi-long-range to short-range order at ρ pinning = 0.02. Interestingly, the dynamics shows a non-monotonic change with increasing the fraction of pinning. This is due to the competition between the disorder that enhances the dynamics and the pinning that hinders the particle motions. Our work highlights the important role of the pinning on the colloidal glass transition, which not only provides a new strategy to prevent crystallization forming glass, but also is helpful for understanding of the vitrification in colloidal systems.


1993 ◽  
Vol 321 ◽  
Author(s):  
M. Li ◽  
W. L. Johnson ◽  
W. A. Goddard

ABSTRACTThermodynamic properties, structures, defects and their configurations of a two-dimensional Lennard-Jones (LJ) system are investigated close to crystal to glass transition (CGT) via molecular dynamics simulations. The CGT is achieved by saturating the LJ binary arrays below glass transition temperature with one type of the atoms which has different atomic size from that of the host atoms. It was found that for a given atomic size difference larger than a critical value, the CGT proceeds with increasing solute concentrations in three stages, each of which is characterized by distinct behaviors of translational and bond-orientational order correlation functions. An intermediate phase which has a quasi-long range orientational order but short range translational order has been found to exist prior to the formation of the amorphous phase. The destabilization of crystallinity is observed to be directly related to defects. We examine these results in the context of two dimensional (2D) melting theory. Finite size effects on these results, in particular on the intermediate phase formation, are discussed.


2008 ◽  
Vol 81 (3) ◽  
pp. 506-522 ◽  
Author(s):  
C. G. Robertson ◽  
C. M. Roland

Abstract We review the literature concerned with the effect of proximity to a filler surface on the local segmental mobility of polymer chains. This mobility is commonly assessed from either the glass transition temperature, Tg, or the segmental relaxation times measured by mechanical, dielectric, or NMR spectroscopy. Published studies report increases, decreases, or no change in Tg upon the addition of carbon black, silica, and other reinforcing fillers. Similarly, the segmental relaxation times have been found to increase or be invariant to the presence of nanometer-sized particles. Some of these discrepancies can be ascribed to ambiguous methods of data analysis; others likely reflect the variation in filler-polymer interaction among different systems. There are unequivocal examples of polymers that have segmental dynamics and glass transitions unaffected by nano-particle reinforcement. However, the general principles governing the behavior remain to be clarified, with further work, focusing on the micromechanics at the particle interface, required for resolution of this important aspect of rubber science and technology.


2019 ◽  
Vol 38 (8) ◽  
pp. 1092-1105 ◽  
Author(s):  
Lijuan Zhao ◽  
Junhong Yang ◽  
Shanshan Wang ◽  
Zhonghua Wu

Sign in / Sign up

Export Citation Format

Share Document