Insight into Clustering in Poly(ethylene oxide) Solutions

The clustering phenomenon has been observed in many macromolecular systems. Poly(ethylene oxide) solutions are characterized by a clustering effect that has been extensively discussed in the literature. Its origin has remained elusive. Using small-angle neutron scattering from PEO solutions in various deuterated solvents, the possible causes of clustering that have been given in the literature are analyzed here. These include impurities in water, possible PEO crystallization, a subtle phase transition whereby a concentrated phase coexists with free polymer coils, hydrogen-bond physical cross-linking, and finally chain ends effect. We have shown that under the experimental conditions considered here (4% PEO weight fraction) the mostly forgotten chain ends effect is at the origin of clustering in poly(ethylene oxide) solutions.

[1]  G. D. Smith,et al.  Molecular dynamics simulation study of hydrogen bonding in aqueous poly(ethylene oxide) solutions. , 2000, Physical review letters.

[2]  D. Ho,et al.  SANS from Poly(ethylene oxide)/Water Systems , 2002 .

[3]  S. Bekiranov,et al.  SOLUTION BEHAVIOR OF POLYETHYLENE OXIDE IN WATER AS A FUNCTION OF TEMPERATURE AND PRESSURE , 1997 .

[4]  W. Brown,et al.  Static and dynamic properties of poly(ethylene oxide) in methanol , 1990 .

[5]  R. Kjellander,et al.  Water structure and changes in thermal stability of the system poly(ethylene oxide)–water , 1981 .

[6]  A. Faraone,et al.  The puzzle of poly(ethylene oxide) aggregation in water: Experimental findings , 1999 .

[7]  P. Flory.  Principles of polymer chemistry , 1953 .

[8]  T. G. M. Ven,et al.  Dilute Aqueous Poly(ethylene oxide) Solutions: Clusters and Single Molecules in Thermodynamic Equilibrium , 1996 .

[9]  G. Karlstroem.  A new model for upper and lower critical solution temperatures in poly(ethylene oxide) solutions , 1985 .

[10]  A second type of phase separation in polymer solutions , 1991 .

[11]  Derek L. Ho,et al.  Clustering of poly(ethylene oxide) in water revisited , 2003 .

[12]  S. Lüsse,et al.  The Interaction of Poly(ethylene glycol) with Water Studied by 1H and 2H NMR Relaxation Time Measurements , 1996 .

[13]  N. Yu,et al.  Macromolecule hydration and the effect of solutes on the cloud point of aqueous solutions of polyvinyl methyl ether: a possible model for protein denaturation and temperature control in homeothermic animals. , 1971, Journal of colloid and interface science.

[14]  W. Burchard,et al.  Static light scattering from aqueous poly(ethylene oxide) solutions in the temperature range 20-90°C , 1983 .

[15]  Elena E. Dormidontova,et al.  Role of Competitive PEO−Water and Water−Water Hydrogen Bonding in Aqueous Solution PEO Behavior , 2002 .

[16]  J. C. Selser,et al.  Polyethylene oxide does not necessarily aggregate in water , 1990, Nature.

[17]  S. Kinugasa,et al.  Aggregative Behavior of Poly(ethylene oxide) in Water and Methanol , 1994 .

[18]  M. Duval.  Monitoring of Cluster Formation and Elimination in PEO Solutions , 2000 .