Insights in the Architecture of Silicon‐Based Plasma Polymers Using Partial Network Ethanolysis Combined with Electrospray Tandem Mass Spectrometry

Abstract

International audienceThin films obtained upon plasma polymerization of D4 and HMDSO precursors at atmospheric pressure are submitted to controlled ethanolysis to produce oligomers amenable to electrospray mass spectrometry. When using high resolution mass spectrometry to assess their elemental composition and tandem mass spectrometry to characterize their end-groups, a whole set of ethanolysis products is identified, from which the network connectivity in the original film can be reconstructed. Ethanolysis products of ppD4 and ppHMDSO exhibit the same structural features composed of linear and cross-linked PDMS moieties, the extent of cross-linking reflecting the inorganic character of the film. Oligomers originally embedded in the solid network and released as intact species upon its dissolution are also observed. [GRAPHICS]

Unraveling the architecture of plasma polymers by electrospray tandem mass spectrometry

“…Specific structural features 342 of these ethanolysis products (such as end-group combination or cyclolinear chains) provided a 343 useful complement to these rules, as summarized in Table 2 [43]. In particular, presence of 344 cycles and/or ramifications along the precursor ion skeleton was observed to strongly modify 345 relative abundances of product ions in MS/MS spectra.…”

“…Amongst ethanolysis products, several oligomeric distributions were surprisingly found to 313 contain neither ethoxy nor hydroxy terminations but trimethylsilyl and trimethylsiloxy end-314 groups [43]. Typical MS/MS spectra obtained after collisional activation of such 315 k C i (trimethylsilyl, trimethylsiloxy) adducted with ammonium are shown in Fig.…”

High-resolution Kendrick Mass Defect Analysis of Poly(ethylene oxide)-based Non-ionic Surfactants and Their Degradation Products

“…4A . It then turns the degradation step into another analytical tool to gain structural insights into the intact sample as proposed in previous articles for the unravelling of complex polymeric networks 49,50 . …”

Convenient visualization of high‐resolution tandem mass spectra of synthetic polymer ions using Kendrick mass defect analysis – the case of polysiloxanes

“…[7] Those studies have highlighted the influence of the end-groups and charge state [8][9][10] or architecture of polysiloxanes [7,11] on their MS/MS fingerprints that are sometimes difficult to describe precisely. The chosen examples comprise the CID of a (trimethylsilyl, methyl)-ended polydimethylsiloxane ((SiC 3 H 9 , CH 3 )-PDMS) [8,10] from Polymer Standard Service (Mainz, Germany), a polycyclic (SiC 3 H 9 , CH 3 )-PDMS from a plasma polymerized hexamethyldisiloxane (PPHMDSO) [12] and an octakis(3-ammoniumpropyl) octasilsesquioxane ((nPrNH 2 )-POSS). [11] Electrospray ionization (ESI)-MS/MS spectra were recorded in positive ion mode using a QStar Elite hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometer from Applied Biosystems/SCIEX (Concord, ON, Canada).…”

“…Polysiloxane chains found in PPHMDSO have been described as polycyclic PDMS chains carrying trimethylsilyl and methyl terminations. [7,12] The ESI-MS/MS spectrum of the ammoniated 10-mer from a (SiC 3 H 9 , CH 3 )-ended polysiloxane distribution with four cyclic rings in its backbone is depicted in Fig. 2(a) with the generic structure of the precursor ion.…”