Novel Functional Polymers:  Poly(dimethylsiloxane)−Polyamide Multiblock Copolymer. 8. Surface Studies of Aramid−Silicone Resin by Means of XPS, Static SIMS, and TEM

Abstract

The surface structures of solvent-cast films with aramid−poly(dimethylsiloxane) (poly(dimethylsiloxane) = PDMS) multiblock copolymers (PASs) that contained 8, 14, 24, 41, and 71 wt % of PDMS were characterized by angular-dependent X-ray photoelectron spectroscopic (XPS) measurements, static secondary ion mass spectrometric (SSIMS) measurements, and transmission electron microscopic (TEM) observations. The results of angular-dependent XPS measurement elucidated that the surface concentration of the PDMS segments was much higher than that in bulk and further increased with a decrease in the sampling depth. In particular, the Si/C ratios that were determined by XPS at a 10° takeoff angle in PAS films that contained more than 24 wt % PDMS were almost the same as that in the PDMS homopolymer. From the results of SSIMS measurement, the outermost surfaces of all of the PAS films were found to be completely covered with a PDMS segment even if the PDMS content was only 8 wt % in bulk. In addition, we visually confirmed the surface enrichment of the PDMS segment by TEM observation. The free surfaces of all PAS films were predominantly covered with a PDMS thin layer, although the microphase-separated structures in bulk were different according to the PDMS content in PAS.

Anti‐thrombogenicity of styrene‐butadiene‐styrene triblock copolymer grafted with poly(ethylene glycol)s

“…Peaks of C 1s at around 290 eV, O 1s at around 530 eV, and Si 2p at around 100 eV were observed in every spectra and F 1s at around 690 eV for cast films. These peaks are slightly deviated from previously reported data, [33][34][35] because of the electron charge on the surface. Silicon atoms are not contained in the purified SBS or the hydrocarboxyl and hydrobrominate SBS.…”

“…Figure 5 shows curve-fitting of the C 1s peaks of cast, hydrocarboxyl, and SBS grafted with three different molecular weights of PEG. 33,34 Table III also contains the data regarding the percentages of CH at 285 eV, CAO of 286.5 eV, C¼ ¼O of 288.0 eV, and COO of 289.3 eV calculated from curve-fitting of each C 1s peak. We can see the data correponding to the COO group in the cases of hydrocarboxyl SBS cast and hydrocarboxyl melt-molded films and hydrocarboxyl BR cast film.…”

New Siloxane‐Organic Polyesters with Azobenzene Side Chains. Synthesis, Thermotropic Behavior and Surface Properties

“…[37][38][39][40][41][42] The explanation of such behavior is the preferential orientation of the siloxane fragments towards the surface due to their very low surface tension. We reported the same observation for modified polysulfones having disiloxane units in the sidechain.…”

Novel Functional Polymers. Poly(dimethylsiloxane)-Polyamide Multiblock Copolymers X. 1H NMR Analysis on Fine Structure of Aramid-Silicone Resin

“…4,5 In the previous reports, we studied the synthesis and characteristics of PAS from the point of view of a novel biomaterial. [6][7][8][9][10][11][12][13][14][15] In that study, PAS exhibited many of the desirable properties of aramid and PDMS for medical applications. The interactions between biomolecules such as protein, cell, and tissue and PAS surfaces were found to be equal or relatively low compared with SILASTIC 500-1.…”

“…We observed the microphase-separated structures of PAS films under TEM. 12,14 Although the microphase-separated structures in bulk were different according to the PDMS content in PAS, XPS static SIMS analyses suggested that the free surface of all PAS films were predominantly covered with a PDMS thin layer. 14 In this paper, we report the detailed 1 H NMR characterization of PAS, because the regularity of chemical structure of copolymer such as PAS, which seem to be strongly influenced by the molding method, play an important role in their functionality, especially in medical applications.…”