TY - JOUR
T1 - Unraveling the Spontaneous Zwitterionic Copolymerization Mechanism of Cyclic Imino Ethers and Acrylic Acid
AU - Steinkoenig, Jan
AU - De Jongh, Patrick A.J.M.
AU - Haddleton, David M.
AU - Goldmann, Anja S.
AU - Barner-Kowollik, Christopher
AU - Kempe, Kristian
PY - 2018/1/23
Y1 - 2018/1/23
N2 - We report a high-resolution electrospray ionization mass spectrometric (HR ESI-MS) access route leading to in-depth insights into the spontaneous zwitterionic copolymerization mechanism between cyclic imino ethers (i.e., 2-methyl-2-oxazoline (MeOx), 2-ethyl-2-oxazoline (EtOx), or 2-ethyl-2-oxazine (EtOz)) with acrylic acid (AA), exploiting the characteristic species accumulating during the copolymerization as well as tandem mass spectrometry (MS/MS). We demonstrate preferences in α, ω-end group formation by screening various feed ratios of cyclic imino ethers and acrylic acid (e.g., MeOx:AA = 1:1; MeOx:AA = 2:1; and MeOx:AA = 1:2). Critically, a calibration curve - based on AA-MeOx-AA dimer - was established allowing for the semiquantitative determination of the end-group ratios with different feed ratios of acrylic acid. The formation of previously suggested alternating copolymers was confirmed by MS/MS experiments. Deviations from an ideal alternating composition were found to decrease from MeOx to EtOx to EtOz. The results of (semiquantitative) HR ESI-MS and MS/MS measurements suggest, for the first time presented in such precision, a polymerization mechanism for the spontaneous zwitterionic (alternating) copolymerization indicating optimal monomer ratios and pairings.
AB - We report a high-resolution electrospray ionization mass spectrometric (HR ESI-MS) access route leading to in-depth insights into the spontaneous zwitterionic copolymerization mechanism between cyclic imino ethers (i.e., 2-methyl-2-oxazoline (MeOx), 2-ethyl-2-oxazoline (EtOx), or 2-ethyl-2-oxazine (EtOz)) with acrylic acid (AA), exploiting the characteristic species accumulating during the copolymerization as well as tandem mass spectrometry (MS/MS). We demonstrate preferences in α, ω-end group formation by screening various feed ratios of cyclic imino ethers and acrylic acid (e.g., MeOx:AA = 1:1; MeOx:AA = 2:1; and MeOx:AA = 1:2). Critically, a calibration curve - based on AA-MeOx-AA dimer - was established allowing for the semiquantitative determination of the end-group ratios with different feed ratios of acrylic acid. The formation of previously suggested alternating copolymers was confirmed by MS/MS experiments. Deviations from an ideal alternating composition were found to decrease from MeOx to EtOx to EtOz. The results of (semiquantitative) HR ESI-MS and MS/MS measurements suggest, for the first time presented in such precision, a polymerization mechanism for the spontaneous zwitterionic (alternating) copolymerization indicating optimal monomer ratios and pairings.
UR - http://www.scopus.com/inward/record.url?scp=85041072207&partnerID=8YFLogxK
U2 - 10.1021/acs.macromol.7b02608
DO - 10.1021/acs.macromol.7b02608
M3 - Article
AN - SCOPUS:85041072207
VL - 51
SP - 318
EP - 327
JO - Macromolecules
JF - Macromolecules
SN - 0024-9297
IS - 2
ER -