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Banded spherulites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-3HV)) random copolymer were prepared by isothermal crystallization at 90 °C for 10 h. Using tapping-mode atomic force microscopy (AFM), the concentric periodic ridges and valleys on the surface of the banded spherulites of this polymer were found to consist of edge-on and flat-on lamellae, respectively. The periodic concentric ridges and valleys observed by AFM corresponded to the periodic extinction rings observed by polarized optical microscopy. AFM measurements showed that the interaction between the AFM probe and the sample surface can be significantly influenced by lamellar orientation.

X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and atomic force microscopy (AFM) were used to investigate the surface composition, structure, and morphology of various poly(styrene-co-p-hexafluorohydroxyisopropyl-α-methylstyrene)/poly(4-vinylpyridine) (PS(OH)/PVPy) blends spanning the immiscibility−miscibility−complexation transition, when the density of the hydrogen bond was adjusted by varying the hydroxyl content of the PS(OH) component. The surface chemical composition of the blends has been shown to be strongly dependent on the density of the hydrogen bonds. XPS results revealed that the intermolecular hydrogen bonding between PS(OH) and PVPy could induce a shift of 0.9−1 and 1.2−1.3 eV in the N 1s and O 1s binding energies, respectively. ToF-SIMS data showed that the absolute intensity of positive secondary ions characteristic of PVPy at m/z = 80, 93, 106, and 120 was enhanced due to the formation of hydrogen bonds. The hydroxyl groups enhanced the formation of pyridine-ring-containing ions, which need one proton in the process of ion fragmentation. The positive ions at m/z = 132, 195, and 209, which are also characteristic of PVPy, showed little enhancement because these ions contain unsaturated double bonds. ToF-SIMS and AFM results showed that the size of the dispersed phase decreased as the density of the hydrogen bond increased.

Two series of sequential polymers were synthesized by polymerization of 1,n-dibromoalkane (n = 4, 6, 8, 10, 12, 14, and 18) with 4,4‘-(hexafluoroisopropylidene)diphenol (6FBA) and bisphenol A (BA). The flexible aliphatic segment length changes from 4 to 21 Å corresponding to 4−18 CH2 groups. The influence of the flexible aliphatic segment length on the surface composition of BA and 6FBA sequential polymers was investigated by XPS and ToF-SIMS. The O 1s/C 1s peak ratios of the BA polymers indicated that the flexible segment was enriched on the BA polymer surface when the number of the CH2 groups was larger than 14 (the length of the flexible segment ~17 Å). The F 1s/C 1s peak ratios of the 6FBA polymers showed that the length of the flexible segment on the surface was the same as the bulk. The ratios between the intensities of the characteristic peaks of the flexible and rigid segments displayed a linear dependence on the surface flexible segment length determined by XPS.

The polymer (BA-C8) was prepared by condensation polymerization of bisphenol A and 1,8-dibromooctane. The bromine atoms that were attached to the ends of the polymer chains could be used to determine the distribution of the end groups on the surface of BA-C8 polymer films. The surface morphology was studied using atomic force microscopy (AFM) tapping mode phase imaging. Direct observation of the growth process of a spherulite indicates that the diameter of the spherulite increases with time. The spatial distribution of the end group, Br, was determined by time-of-flight secondary ion mass spectrometry (ToF−SIMS) chemical imaging. For the amorphous films, a homogeneous distribution of the end groups at the surface was found, while for the semicrystalline films the end groups rearranged and preferentially segregated at the surface of the boundaries and the eyes of the spherulites.

Poly(N-vinylcarbazole) (PVK) was sulfonated with acetyl sulfate. SIMS and XPS measurements of the sulfonated PVK show that the sulfonation occurs on the carbazole moiety and that the degree of sulfonation (DS) increases linearly with the ratio of the sulfonating agent to PVK. The DS of PVK could be controlled within a range from 12% to 28% by varying the reagent ratio. GPC measurements demonstrate that the molecular weight of PVK did not change substantially after sulfonation. UV−vis and photoluminescence spectra indicate that the sulfonation caused little change in the electronic structure of the PVK molecules but reduced significantly its photoluminescence quantum efficiency.

The specific interaction of hydrogen bonding between poly(styrene-co-4-vinylphenol) (STVPh) and poly(styrene-co-4-vinylpyridine) (STVPy) was investigated by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The density of the hydrogen bond was adjusted by varying the 4-vinylphenol (VPh) content in the STVPh copolymers. Immiscible blends were formed when the VPh content was low, and an interpolymeric complex was formed when the VPh content was above a certain value. In addition, an interpolymer complex was formed between poly(4-vinylphenol) (PVPh) and STVPy-72 (containing 72 mol % of Py). For the complexes, XPS results revealed that the intermolecular hydrogen bonds between the hydroxyl and pyridyl units can induce a shift of 0.6−0.7 eV and 0.4−0.5 eV in the N 1s and O 1s binding energies, respectively. Such large shifts in the binding energy may imply that the nitrogen is partially protonated. The XPS results also showed that STVPy-72 was enriched on the surface of immiscible blends of STVPy-72 and STVPh-y (where y is the mol % of VPh, y = 1, 9, and 22). However, surface segregations of STVPh-50 and PVPh were detected respectively for the complex between STVPh-50 and STVPy-72 and the complex between PVPh and STVPy-72. The intensity ratios of the ions for the complexes that were affected by the formation of hydrogen bonding, such as C5H6N⁺/C5H5N⁺ and C6H7N⁺/C6H6N⁺, were larger than those in the STVPy-72 copolymer. The intensity ratios of these ions for immiscible blends of STVPh and STVPy-72 and for the STVPy-72 copolymer were almost the same. The results indicate that hydrogen bonding plays an important role in the distribution of the peak intensities of the ions that are affected by the formation of hydrogen bonding in a SIMS process.

The results obtained with three surface spectroscopic methods (XPS, ISS, and static SIMS with quadrupole or time-of-flight analyzers) available for the characterization of the particle surface of polystyrene latexes have been compared. The main point was to quantify the desorption of the surfactants used in the emulsion polymerization (Aerosol MA and sodium dodecylbenzenesulfonate) by the study of both unpurified and purified latexes. A comparison was made between these results and those obtained on a latex prepared by emulsion polymerization without any tensioactive stabilizer, therefore bearing only sulfate groups issued from the initiator. Sodium dodecyl sulfate was used as a reference for the presence of sulfate groups. The pure emulsifiers were also investigated separately. The various samples were analyzed as either powders or films, and the results obtained on films are discussed in terms of the migration of the surfactant toward the interface during the preparation of the films. On the other hand, our results showed clearly that static SIMS with a time-of-flight analyzer is the most suitable technique to study the desorption of emulsifier from latex particles. These results demonstrate that, after extensive purification by mixed-bed ion exchange resins, the strong acid emulsifier (Aerosol MA) can be completely desorbed.

Poly(methylmethacrylate) (PMMA) and polystyrene (PS) thin films of different tacticities have been analysed by time-of-flight (ToF) SIMS in order to look for a possible influence of the stereoregularity on their fingerprint spectra (m/z200). Because, at first glance, the spectra of samples with different tacticities seemed rather similar, the intensity ratios between secondary ions from main polymer chain and those from pendant group were evaluated. By this procedure, it was found that isotactic PMMA can be clearly distinguished from syndiotactic and atactic PMMA. A lower concentration of the methyl-methacrylate pendant group was detected at the surface of the isotactic sample. In the case of PS, more phenyl groups were found to be present at the surface of isotactic PS and an empirical criterion is proposed to differentiate between atactic and isotactic PS. © 1997 by John Wiley & Sons, Ltd.

A blend of poly(ε-caprolactone) (PCL) and poly(vinyl chloride) (PVC) with 90 wt % PCL was prepared. Two films of this blend, which were grown at 35 and 45 °C, showed the absence and presence of banded spherulites, respectively. A detailed examination conducted with time-of-flight secondary ion mass spectrometry (ToF−SIMS) found that the surface composition of the film grown at 45 °C was related to its structure, which was shown to contain ridges and valleys. Phase images obtained using atomic force microscopy (AFM) indicated that the ridges and valleys consisted of edge-on and flat-on lamellae, respectively. ToF−SIMS imaging revealed that PVC and PCL were located mainly on the surface of the valleys and ridges, respectively. This morphology-driven surface segregation was caused by the difference in the surface energy between the flat-on and edge-on lamellae.