TY - JOUR
T1 - Crystallization and vitrification of a cyanurate trimer in nanopores
AU - Koh, Yung P.
AU - Simon, Sindee L.
PY - 2012/7/5
Y1 - 2012/7/5
N2 - The effects of nanopore confinement on the crystallization and vitrification of a low molecular weight organic material, tris(4-cumylphenol)-1, 3,5-triazine, are investigated using differential scanning calorimetry. The material shows cold crystallization and subsequent melting in the bulk state. Under the nanoconfinement of controlled pore glasses (CPG), cold crystallization and melting shift to lower temperatures. Crystallization kinetics are hindered in nanoconfinement, and no crystallization occurs in 13 nm diameter pores over the course of a week. Using a traditional Avrami analysis, the restricted crystallization under nanopore confinement is quantified; for crystallization at 80 °C, the Avrami exponent decreases with decreasing pore size and the overall crystallization rate is approximately 30 times slower for material confined in 50 nm diameter pores than the bulk. When compared at the temperature at which the crystallization rate is a maximum, the Avrami exponent is higher in nanoconfined samples and the crystallization rate is approximately 10 times slower for material confined in 50 nm diameter pores. Under CPG nanoconfinement, the glass transition temperature also decreases and shows two values; interestingly, the Tg values further decrease with increasing crystallinity.
AB - The effects of nanopore confinement on the crystallization and vitrification of a low molecular weight organic material, tris(4-cumylphenol)-1, 3,5-triazine, are investigated using differential scanning calorimetry. The material shows cold crystallization and subsequent melting in the bulk state. Under the nanoconfinement of controlled pore glasses (CPG), cold crystallization and melting shift to lower temperatures. Crystallization kinetics are hindered in nanoconfinement, and no crystallization occurs in 13 nm diameter pores over the course of a week. Using a traditional Avrami analysis, the restricted crystallization under nanopore confinement is quantified; for crystallization at 80 °C, the Avrami exponent decreases with decreasing pore size and the overall crystallization rate is approximately 30 times slower for material confined in 50 nm diameter pores than the bulk. When compared at the temperature at which the crystallization rate is a maximum, the Avrami exponent is higher in nanoconfined samples and the crystallization rate is approximately 10 times slower for material confined in 50 nm diameter pores. Under CPG nanoconfinement, the glass transition temperature also decreases and shows two values; interestingly, the Tg values further decrease with increasing crystallinity.
UR - http://www.scopus.com/inward/record.url?scp=84863621340&partnerID=8YFLogxK
U2 - 10.1021/jp303318e
DO - 10.1021/jp303318e
M3 - Article
C2 - 22670859
AN - SCOPUS:84863621340
SN - 1520-6106
VL - 116
SP - 7754
EP - 7761
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 26
ER -