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Title: Assessing Chemical Transformation of Reactive, Interfacial Thin Films Made of End-Tethered Poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) Chains

Designing thin films or surface scaffolds with an appropriate display of chemical functionality is useful for biomedical applications, sensing platforms, adhesives, and barrier coatings. Relationships between the structural characteristics of model thin films based on reactive poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) brushes and the amount and distribution of primary amines used to chemically functionalize these layers in situ are quantitatively detailed via neutron reflectometry and compared with results from ellipsometry. After functionalization, the PVDMA brush thickness increases as a result of the primary amines reacting with the azlactone rings. Both techniques show that the extent of functionalization by small-molecule amines depends on the size of the amine, the grafting density of brush chains, and their molecular weight. However, constrained analysis of neutron reflectivity data predicated on that technique’s sensitivity to isotopic substitution and its ability to resolve structure at the nanoscale shows that the extent of functionalization is not accurately represented by the average extent of functionalization determined from ellipsometric thickness: reactive modification is not uniform, even in modestly dense brushes, except when the penetrant is small. In addition, there appears to be a loss of PVDMA chains during functionalization, attributed to chain scission resulting from additional stretching brought about by functionalization.more » In conclusion, these findings provide unprecedented insight into the alteration of surface properties by reactive modification and broadly support efforts to produce tailored surfaces in which properties such as friction, colloidal stability, adhesion, wettability, and biocompatibility can be modulated in situ by chemical modification.« less
Authors:
 [1] ;  [1] ;  [2] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4] ; ORCiD logo [5]
  1. Univ. of Tennessee, Knoxville, TN (United States). Department of Chemistry
  2. Univ. of Tennessee, Knoxville, TN (United States). Department of Chemical and Biomolecular Engineering
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS) ; Univ. of Tennessee, Knoxville, TN (United States). Department of Chemistry and Department of Chemical and Biomolecular Engineering
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Macromolecules
Additional Journal Information:
Journal Volume: 50; Journal Issue: 2; Journal ID: ISSN 0024-9297
Publisher:
American Chemical Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE
OSTI Identifier:
1426561