Polymer Dynamics

The goals of this research are to understand the dynamics (molecular motion) in polymeric systems and to relate this understanding to the physical and chemical properties of the systems. The study of dynamics is important because the microstructure and dynamics of the polymeric system ultimately determine the macroscopic properties of the material. In our group, we use solid and liquid nuclear magnetic resonance (NMR), modulated differential scanning calorimetry (MDSC), FTIR, and mechanical properties as the primary probes. The majority of these studies have been focused on the properties of polymers in solution, bulk and at solid interfaces:

Many of the studies done in our group use specific isotope labelling and deuterium NMR which has several advantages including that: i) the dynamics are easily inferred from deuterium NMR spectra because the NMR relaxation times and line shapes are dominated by electric quadrupole effects. ii) specific enrichment with deuterium greatly increases in sensitivity and removes most problems associated overlapping resonances. The deuterium NMR technique is an effective nonperturbing method of probing dynamics.

Polymer solids show some direct relationships between polymer motion and physical properties. However, detailed knowledge of polymer motion in the solid state is lacking. We have focused our efforts on determining polymer motion from deuterium NMR lineshapes, both 1- and 2-dimensional and relaxation times.

Dynamics of Adsorbed Polymers
From 1-D Deuterium NMR Lineshapes and Relaxation Phenomena

Homopolymers

209. a. - M.O. Okuom, B. Metin, F.D. Blum, Segmental Dynamics of Poly(Methyl Acrylate)-d3 Adsorbed on Anopore - A Deuterium NMR Study, Langmuir, 24, 2539-2544 (2008). DOI: 10.1021/la703103j
200. B. Metin and F. D. Blum Segmental Dynamics in Poly(methyl acrylate) on Silica: Molecular-Mass Effects, J. Chem. Phys., 125, 054707-9 (2006). DOI:10.1063/1.2219739
174. a - F D. Blum, B. Gandhi, D. Forciniti, and L. Dharani, Effect of Surface Segmental Mobility on the Adhesion of Acrylic Soft Adhesives, Macromolecules, 38, 481-487(2005).
158. F. D. Blum, W.-Y. Lin, C. E. Porter, Dynamics of Adsorbed Poly(methyl acrylate) and Poly(methyl methacrylate) on Silica, Colloid Polym Sci., 281, 197-202 (2003).
150. F. D. Blum, Graded Interfaces of Polymers on Silica, Silica 2001 CD-ROM, Institut de Chimie des Surfaces et Interfaces, ICSI-CNRS, Mulhouse, France, paper 223, 4pp, 2001.
145.W.-Y. Lin and F.D. Blum, Segmental Dynamics of Interfacial Poly(methyl acrylate)-d3 in Composites by Deuterium NMR Spectroscopy, J. Amer. Chem. Soc., 123, 2032-2037 (2001).
129. W.-Y. Lin and F. D. Blum, Segmental Dynamics of Bulk and Adsorbed Poly(methyl acrylate)-d3 by Deuterium NMR: Effect of Molecular Weight, Macromolecules, 31, 4135-4142 (1998).
124. W.-Y. Lin and F. D. Blum, Segmental Dynamics of Bulk and Adsorbed Poly(methyl acrylate)-d3 by Deuterium NMR: Effect of Adsorbed Amount, Macromolecules 30, 5331-5338 (1997).
121. F.D. Blum, G. Xu, M. Liang, C.G. Wade, Dynamics of Poly(vinyl acetate) in Bulk and on Silica, Macromolecules, 29, 8740-8745 (1996).
119. M. Liang, F.D. Blum, Segmental Motion in Surface-Bound Swollen Poly(methyl acrylate), Macromolecules, 29, 7374-7377 (1996).
72. F.D. Blum, R.B. Funchess, W. Meesiri, Dynamics of Surface Bound Polymers and Coupling Agents, Solid State NMR of Polymers, L. Mathias, Ed., Plenum Press, New York, 1991, p271-281.

Block Copolymers

128. M. Xie and F. D. Blum, Segmental Dynamics of Poly(styrene-b-2-vinylpyridine) in Bulk and at the Surface/Air Interface, J. Polym. Sci.-Polym. Phys. Ed., 36, 1609-1616 (1998).
120. M. Xie, F.D. Blum, Adsorption and Dynamics of Poly(styrene-b-2-vinylpyridine) on Silica and Alumina in Toluene, Langmuir, 12, 5669-5673 (1996).
86. B.R. Sinha, F.D. Blum, F.C. Schwab, Dynamics of Adsorbed, Swollen Block Copolymers, Macromolecules, 26, 7053-7057 (1993).
59. F.D. Blum, B.R. Sinha, F.C. Schwab, Density Profile of Terminally Attached Polymers, Macromolecules, 23, 3592-3598 (1990).

Physical Properties of Adsorbed Polymers
Thermal Behavior and Infrared Behavior of Adsorbed Polymers

228pic 228. a-M. Maddumaarachchi, F. D. Blum, Thermal Analysis and FT-IR Studies of Adsorbed Poly(ethylene-stat-vinyl acetate) on Silica, J. Polym. Sci. B, Polym. Phys., 2014, in press. DOI: 10.1002/polb.23476

203. a. - M. T. Kabomo, F. D. Blum, S. Kulkeratiyut, S. Kulkeratiyut, P. Krisanangkura, Effects of Molecular Mass and Surface Treatment on Adsorbed Poly(methyl methacrylate) on Silica, J. Polym. Sci.: B: Polym. Phys., 46, 649-658 (2008). DOI: 10.1002/polb.21400
195. F. D. Blum, E. N. Young, G. Smith and O. C. Sitton, Thermal Analysis of Adsorbed PMMA on Silica, Langmuir, 22, 4741-4744 (2006).
157. B. Zhang and F.D. Blum, Thermogravimetric Study of Ultra-thin PMMA Films on Silica: Effects of Tacticity, Thermochimica Acta, 396, 211-217 (2003).
155. C. Porter and F. D. Blum, Thermal Characterization of Adsorbed Polystyrene Using Modulated Differential Scanning Calorimetry, Macromolecules, 35, 7448-7452 (2002).
142. C. E. Porter and F.D. Blum, Thermal Characterization of PMMA Thin Films Using Modulated Differential Scanning Calorimetry, Macromolecules, 33, 7016-7020 (2000).

Adhesion in Thin Films
198. F. D. Blum, R. Vohra, B. Metin, O. C. Sitton, Surface Segmental Mobility and Adhesion - Effects of Filler and Molecular Mass, J. Adhesion, 82, 903-917 (2006). DOI:10.1080/00218460600875920

Bound Carbonyls - IR
197. S. Kulkeratiyut, S. Kulkeratiyut, F. D. Blum, Determination of Bound Carbonyls in PMMA Adsorbed on Silica Using Transmission FTIR, J. Polym. Sci., B, Polym. Phys. Ed, 44, 2071-2078 (2006).

Structure and Dynamics of Bulk Polymers
From 2D Deuterium NMR
189. B. Metin and F.D. Blum, Molecular Mass and Dynamics of Poly(methyl acrylate) in the Glass Transition Region, J. Chem. Phys., 124, 054908-10 (2006).
140. R.D. O'Connor, E. Ginsberg, and F.D. Blum, Solid-state Deuterium NMR of Methyl Dynamics of Poly(α-methylstyrene) and Polymethylphenylsilane, J. Chem. Phys., 112, 7247-7259 (2000).
130. R. D. O'Connor, F. D. Blum, E. Ginsburg, and R. D. Miller, Dynamics of Polymethyl-phenylsilane-d3 by Two-Dimensional Exchange NMR, Macromolecules, 31, 4852-4861 (1998).

From 1-D Deuterium NMR
7. F.D. Blum, J.E. Dickson and W.G. Miller, Effect of Diluents on Poly(vinyl acetate) Dynamics, J. Polym. Sci., Polym. Phys. Ed., 22, 211-221 (1984).

From CP-MAS NMR
71. R.J. Gambogi, D.L. Cho, H. Yasuda, F.D. Blum, Characterization of Plasma Polymerized Hydrocarbons Using Carbon-13 NMR, J. Polym. Sci., Polym. Chem. Ed., 29, 1801-1805 (1991).
50. B.R. Sinha, F.D. Blum and D. O'Connor, Characterization of Substituted Phenol-Formaldehyde Resins Using Solid-State Carbon-13 NMR, J. Appl. Polym. Sci., 38, 163-171 (1989).

Simulations/Models
39. S. Jagannathan, F.D. Blum and C.F. Polnaszek, Computer Simulation of Deuterium NMR Lineshapes, J. Chem. Inf. Comput. Sci., 27, 167-170 (1987).

In solution NMR studies can provide very stringent tests for models of polymer reorientation. We have shown that most of the existing motional theories of polymer dynamics in solution are not capable of mimicking the deuterium relaxation data in a physically realistic way. We have found other ways to use the relaxation data in more qualitative ways to study the effects of composition and temperature on polymer dynamics. This has important consequences in concentrated solutions where the effects of plasticization can be probed. We have also demonstrated some relationships between the segmental motion of the polymer and the diffusion of the solvents.

The same experimental techniques, which are used in polymer reorientation, can also be used to study the reorientation of various diluents in polymeric systems. The dynamics studies can yield information concerning mobility and polymer-diluent interactions. We are currently observing the dynamics of so called "good" solvents, but plan to extend this to plasticizers which are commonly used. In this case the relationship between the mobility of the plasticizers and their ability to plasticize the polymer system will be probed. Again the goal is to relate the microscopic dynamics with the physical properties of the system.

Dynamics of Polymers in Solution
156. F. D. Blum and R. B. Durairaj, Local Segmental Dynamics of Polyacrylates in Concentrated Chloroform Solutions, NMR Spectroscopy of Polymers in Solution and in the Solid State, ACS Symposium Series, #843, American Chemical Society, Washington, DC, H.N. Cheng and A. English, eds. 398-408, 2002.
112. M. Xie and F.D. Blum, Dynamics of Poly(styrene-b-2-vinylpyridine) in Toluene, Macromolecules, 29, 3862-3867 (1996).
91. R.D. O'Connor, F.D. Blum, Log-χ2 Distribution of Correlation Times Revisited, Macromolecules, 27, 1654-1656 (1994).
10. F.D. Blum, B. Durairaj and A.S. Padmanabhan, Backbone Dynamics of Poly(isopropyl acrylate) in Chloroform. A Deuterium NMR Study, Macromolecules, 17, 2837-2846 (1984).

Diluent Mobility
77. B. naNagara, R.D. O'Connor, F.D. Blum, Mobility of Toluene in Polystyrene-Toluene Solutions. A NMR Study, J. Phys. Chem., 96, 6417-6423 (1992).
37. F.D. Blum and B. na Nagara, Solvent Mobility in Atactic Polystyrene-Toluene Systems, in Reversible Polymer Gels, P.S. Russo, Ed., American Chemical Society Symposium Series, 350, 107-114 (1987).
26. F.D. Blum, A.S. Padmanabhan and B. Durairaj, Solvent Self-Diffusion, Polymer NMR Relaxation and Free Volume in Polymer Solutions, J. Polym. Sci., Polym. Phys. Ed., 24, 493-502 (1986).

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