TY - JOUR
T1 - Relationship between particle elasticity, glass fragility, and structural relaxation in dense microgel suspensions
AU - Seekell, Raymond P.
AU - Sarangapani, Prasad S.
AU - Zhang, Zexin
AU - Zhu, Yingxi
N1 - Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2015/7/21
Y1 - 2015/7/21
N2 - "Fragile" glassy materials, which include most polymeric materials and organic liquids, exhibit a steep and super-Arrhenius dependence of relaxation time with temperature upon the glass transition and have been extensively studied. Yet, a full understanding of strong glass formers that exhibit an Arrhenius dependence on temperature is still lacking. In this work, we have investigated the glassy dynamics of poly(N-isopropylacrylamide) (PNIPAM) microgel particles of varied elasticity in dense aqueous suspensions, giving rise to a full spectrum of strong to fragile glass-forming behaviors. We have observed the dependence of particle motions and structural relaxation on particle volume fraction can be weakened by decreasing particle elasticity, due to particle deformation and the resulting interparticle elastic interaction upon intimate particle contacts at high particle concentration. Both measured α-relaxation time scales and dynamic length scales for cooperative rearranging motions of microgels in suspensions show similarly dependence on particle volume fraction and elasticity, thereby quantifying the glass fragility of dense microgel suspension of varied particle elasticity.
AB - "Fragile" glassy materials, which include most polymeric materials and organic liquids, exhibit a steep and super-Arrhenius dependence of relaxation time with temperature upon the glass transition and have been extensively studied. Yet, a full understanding of strong glass formers that exhibit an Arrhenius dependence on temperature is still lacking. In this work, we have investigated the glassy dynamics of poly(N-isopropylacrylamide) (PNIPAM) microgel particles of varied elasticity in dense aqueous suspensions, giving rise to a full spectrum of strong to fragile glass-forming behaviors. We have observed the dependence of particle motions and structural relaxation on particle volume fraction can be weakened by decreasing particle elasticity, due to particle deformation and the resulting interparticle elastic interaction upon intimate particle contacts at high particle concentration. Both measured α-relaxation time scales and dynamic length scales for cooperative rearranging motions of microgels in suspensions show similarly dependence on particle volume fraction and elasticity, thereby quantifying the glass fragility of dense microgel suspension of varied particle elasticity.
UR - http://www.scopus.com/inward/record.url?scp=84934344115&partnerID=8YFLogxK
U2 - 10.1039/c5sm00640f
DO - 10.1039/c5sm00640f
M3 - Article
AN - SCOPUS:84934344115
SN - 1744-683X
VL - 11
SP - 5485
EP - 5491
JO - Soft Matter
JF - Soft Matter
IS - 27
ER -