Thermal behaviour of perfluoropolyether W/O percolative microemulsions

被引:13
作者
Senatra, D
Gambi, CMC
Carlà, M
Chittofrati, A
机构
[1] Univ Florence, Dept Phys, INFM Grp, I-50125 Florence, Italy
[2] Ausimont SPA, Ctr Res & Dev, Colloid Lab, Milan, Italy
来源
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY | 1999年 / 56卷 / 03期
关键词
DSC of percolative microemulsions; fluorinated compounds; free water; higher order phase transitions by thermal analysis;
D O I
10.1023/A:1010106523289
中图分类号
O414.1 [热力学];
学科分类号
摘要
The thermal properties of a perfluoropolyether (PFPE) W/O microemulsion were investigated by Differential Scanning Calorimetry (DSC) both on freezing the liquid samples and upon their melting. PFPE systems as a function of increasing volume fraction (Phi=water+surfactant/total), were studied along a dilution line with a water/surfactant molar ratio W/S=11. The percolative nature of these systems emerged directly from the spreading of the exothermic peaks associated with the freezing of the dispersed phase. This behaviour was found to depend on whether the starting temperature of the DSC measure was at, below or above the percolative threshold temperature of the given sample. A low temperature 'needle-like' peak was found around 143 K, immediately after the glass transition due to the oil continuous phase. The low temperature peak was also present in other percolative, three-component microemulsions. The higher order phase transition at the percolation temperature was also evidenced.
引用
收藏
页码:1335 / 1346
页数:12
相关论文
共 15 条
[1]   SANS on fluorinated water-in-oil microemulsions [J].
Baglioni, P ;
Gambi, CMC ;
Giordano, R .
PHYSICA B, 1997, 234 :295-296
[2]   SANS study of a fluorinated water-in-oil microemulsion [J].
Baglioni, P ;
Gambi, CMC ;
Giordano, R ;
Senatra, D .
JOURNAL OF MOLECULAR STRUCTURE, 1996, 383 (1-3) :165-169
[3]  
CHITTOFRATI A, 1989, PROG COLL POL SCI S, V79, P218
[4]   Dynamic percolation in fluorinated water-in-oil microemulsions [J].
Gambi, CMC ;
Giri, MG ;
Carla, M ;
Senatra, D ;
Chittofrati, A .
PHYSICAL REVIEW E, 1997, 56 (04) :4356-4363
[5]   PERCOLATION PHENOMENON ON FLUORINATED WATER-IN-OIL MICROEMULSIONS - THE EFFECT OF TEMPERATURE [J].
GIRI, MG ;
CARLA, M ;
GAMBI, CMC ;
SENATRA, D ;
CHITTOFRATI, A ;
SANGUINETI, A .
PHYSICAL REVIEW E, 1994, 50 (02) :1313-1316
[6]   Microstructure of perfluoropolyether water/oil microemulsions [J].
Monduzzi, M ;
Knackstedt, MA ;
Ninham, BW .
JOURNAL OF PHYSICAL CHEMISTRY, 1995, 99 (50) :17772-17777
[7]   PERFLUOROPOLYETHER WATER OIL MICROEMULSIONS - A H-1-NMR SELF-DIFFUSION STUDY OF WATER [J].
MONDUZZI, M ;
CHITTOFRATI, A ;
VISCA, M .
LANGMUIR, 1992, 8 (05) :1278-1284
[8]   LIGHT-SCATTERING STUDY OF A PERFLUOROPOLYETHER TERNARY-SYSTEM [J].
SANGUINETI, A ;
CHITTOFRATI, A ;
LENTI, D ;
VISCA, M .
JOURNAL OF COLLOID AND INTERFACE SCIENCE, 1993, 155 (02) :402-408
[9]   DSC spectra as thermal fingerprints of percolative microemulsions [J].
Senatra, D ;
Pratesi, R ;
Pieraccini, L .
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, 1998, 51 (01) :79-90
[10]  
SENATRA D, 1991, PROG COLL POL SCI S, V84, P122