Comparison of surface structures of poly(ethyl methacrylate) and poly(ethyl acrylate) in different chemical environments
- 6 May 2005
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Physical Chemistry Chemical Physics
- Vol. 7 (11), 2357-2363
- https://doi.org/10.1039/b501910a
Abstract
Sum frequency generation (SFG) vibrational spectroscopy has been applied to investigate and compare the chemical structures of poly(ethyl methacrylate) (PEMA) and poly(ethyl acrylate) (PEA) in air, in water, and in a non-polar solvent, FC-75. SFG spectra from both polymer surfaces in air are dominated by vibrational modes from the ester ethyl side groups. The average orientation of these ester ethyl groups on the two polymer surfaces is slightly different. In water, the two polymers show markedly different restructuring behavior. The ester ethyl side chains on the PEMA surface in water reorient to tilt more toward the surface, yet remain ordered. Such a restructuring of the PEMA surface in water is reversible. However, no SFG signal was detected from the PEA/water interface, showing that the surface of PEA becomes disordered upon contacting water, and this process is irreversible. SFG results collected from the CO range indicate that hydrogen bonding is observed for both polymer/water interfaces, but the order of CO at the PEA/water interface is much lower than that at the PEMA/water interface. Supplemental experiments support our hypothesis that the PEA surface becomes rough and loses order gradually as it interacts with water. We have demonstrated, for the first time, that the loss of surface structural order is due to the interaction between soft PEA chains with water molecules followed by reorganization of the polymer backbone. This causes the polymer surface to become rough and disordered. However, the surface structures of PEMA and PEA in FC-75 are similar and are also similar to those in air. This indicates that not only Tg, but also the contacting medium plays an important role in determining the surface restructuring behavior of polymer materials.Keywords
This publication has 36 references indexed in Scilit:
- Molecular Structure of an Alkyl-Side-Chain Polymer−Water Interface: Origins of Contact Angle HysteresisLangmuir, 2004
- Hydrosilation-Cured Poly(dimethylsiloxane) Networks: Intrinsic Contact Angles via Dynamic Contact Angle AnalysisMacromolecules, 2003
- Investigation of the Water-Induced Reorganization of Polycaprolactone−Poly(fluoroalkylene oxide)−Polycaprolactone Triblock Copolymer Films by Angle-Dependent X-ray Photoelectron SpectroscopyMacromolecules, 2002
- Different Surface-Restructuring Behaviors of Poly(methacrylate)s Detected by SFG in WaterJournal of the American Chemical Society, 2001
- Integration of Bulk and Interfacial Properties in a Polymeric System: Rubber Elasticity at a Polybutadiene/Water InterfaceJournal of the American Chemical Society, 2001
- Environment-Induced Surface Structural Changes of a Polymer: An in Situ IR + Visible Sum-Frequency Spectroscopic StudyThe Journal of Physical Chemistry B, 1997
- Water-Induced Surface Rearrangements of Poly(dimethylsiloxane−urea−urethane) Segmented Block CopolymersChemistry of Materials, 1996
- Quantitative Analysis of Polymer Surface RestructuringLangmuir, 1995
- Observation of Surface Rearrangement of Polymers Using ESCAJournal of Colloid and Interface Science, 1993
- Dynamics of the surface configuration change of polymers in response to changes in environmental conditions. 2. Comparison of changes in air and in liquid waterLangmuir, 1992