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Polymers have a wide range of applications depending on their composition, size, and architecture. Varying any of these three characteristics can greatly impact the resulting chemical, physical, and mechanical properties. While many techniques are available to determine polymer composition and size, determining the exact polymer architecture is more challenging. Herein, tandem mass spectrometry (MS/MS) and ion mobility mass spectrometry (IM-MS) methods are utilized to derive crucial architectural information about dithiol-yne comb polymers. Based on their unique fragmentation products and IM drift times, dithiol-yne oligomers with distinct architectures were successfully differentiated and characterized. Additionally, experimental collision cross-sections (Ω) derived via IM-MS were compared to theoretically extracted Ω values from molecular dynamics simulated structures to deduce the architectural motif of these comb oligomers. Overall, this work demonstrates the benefits of combining various mass spectrometry techniques in order to gain a complete understanding of a complex polymer mixture.

Matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) is an essential analytical technique for the molecular characterization of biomolecules and synthetic polymers. Its ability to provide comprehensive compositional information not afforded by other techniques, with high sensitivity and selectivity, is highly influenced by the sample preparation of the material prior to analysis. This review discusses MALDI-MS sample preparation protocols that do not utilize solvents. Such methods provide alternative routes for analyzing insoluble polymeric materials and may also reveal information that is not attainable with solvent-based sample preparation techniques. Additionally, this review will present relevant surface analysis and imaging results only achievable with solvent-free sample preparation methodologies.

Thermotropic order-order phase transitions (OOTs) in block copolymers are not commonly observed in the strong segregation region. Phase separation of giant surfactants composed of hydrophilic molecular nanoparticles (MNPs) as heads and hydrophobic flexible polymer chains as tails occurs generally in the strong segregation region. By introducing a rigid molecular segment at the junction point of the giant surfactants, the interface between the MNPs and polymer tails could be delicately manipulated, resulting in the occurrence of thermotropic OOTs that are sensitively dependent on the properties of those junction segments. For samples with hydrophilic junction segments, no thermal-induced OOT has been observed. However, for samples with hydrophobic junction segments, complicated thermotropic OOTs between as many as four different ordered phases in a single giant surfactant system, from lamellae (LAM) to hexagonally perforated layer structure (HPL), double gyroids (DG), and finally to hexagonally packed cylinders (HEX), have been observed with increasing temperature. These results demonstrated that interfacial engineering could be used to regulate the self-assemble behavior of macromolecules at the nanometer scales.

Polyether based side-chain liquid crystalline (SCLC) copolymers with distinct microstructures were prepared using living anionic polymerization techniques. The composition, end groups, purity, and sequence of the resulting copolymers were elucidated by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and tandem mass spectrometry (MS/MS). MALDI-MS analysis confirmed the presence of (CH3)3CO− and −H end groups at the initiating (α) and terminating (ω) chain end, respectively, and allowed determination of the molecular weight distribution and comonomer content of the copolymers. The comonomer positions along the polymer chain were identified by MS/MS, from the fragments formed via C−O and C−C bond cleavages in the polyether backbone. Random and block architectures could readily be distinguished by the contiguous fragment series formed in these reactions. Notably, backbone C−C bond scission was promoted by a radical formed via initial C−O bond cleavage in the mesogenic side chain. This result documents the ability of a properly substituted side chain to induce sequence indicative bond cleavages in the polyether backbone.

In this article, we report the facile synthesis, self-assembly, and characterization of shape amphiphiles (BPOSS-PDI-X) based on isobutyl-functionalized polyhedral oligomeric silsesquioxane (BPOSS), perylene tetracarboxylic diimide (PDI), and (60)fullerene (C60) moieties. Firstly, an asymmetrically functionalized diblock shape amphiphile precursor (BPOSS-PDI-OH) was obtained through the one-pot reaction between perylene-3,4,9,10-tetracarboxylic dianhydride and two different amines, namely BPOSS-NH2 and 3-amino-1-propanol. It was further conjugated with C60-COOH to give a tri-block shape amphiphile (BPOSS-PDI-C60). Their chemical structures were thoroughly characterized by NMR, IR and MALDI-TOF MS spectrometry. In order to gain insights on the structure-property relationship, their self-assembly in gas phase, in solution, and in solid state were characterized using traveling wave ion mobility mass spectrometry (TWIM-MS), UV/Vis absorption, fluorescence emission spectrophotometer, and transmission electron microscopy, respectively. It was found that BPOSS-PDI-OH formed more complicated dimers than BPOSS-PDI-C60. Both samples showed unique aggregation behaviors in solution with increasing concentration, which could be attributed neither to H- nor to J-type and might be related to the discrete dimers. While BPOSS-PDI-C60 could hardly crystalize into ordered structures, BPOSS-PDI-OH could form nanobelt-shaped single crystals, which may hold potential applications in microelectronics.

Organic–inorganic hybrid coatings were formulated using multifunctional vinyltrimethoxysilane (VTMS) oligomers and acrylated polyester (AP). A radical photoinitiator was added to the VTMS/AP formulation and the films were crosslinked via UV‐radiation. The viscoelastic, thermomechanical, and surface properties of the VTMS/AP films were evaluated as a function of VTMS content, using dynamic mechanical thermal analysis (DMTA), thermal gravimetric analysis (TGA), contact angle, fracture toughness, and tensile properties. In addition, coating properties such as adhesion, scratch resistance, pencil hardness, and impact resistance were also investigated. The tensile and scratch data show that VTMS oligomer dramatically increased hardness and scratch resistance. The VTMS oligomer also increased the contact angle, led to a decrease in surface tension, and improved surface appearance. The VTMS oligomer also increases storage modulus, glass transition temperature, and crosslink density. The morphology of films and the particle size were observed using atomic force microscopy (AFM). The data indicated that the average silica particle size was ∼90 nm and the particles were well‐dispersed in the organic phase. It was postulated that the VTMS oligomer functioned effectively as a hyperbranched crosslinker, surface modifier, and reactive diluent. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105:2376–2386, 2007 [ABSTRACT FROM AUTHOR]

The chain‐end‐group composition was determined by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) analyses of low‐molecular‐weight polystyrene (PS) and poly(methyl methacrylate) (PMMA) produced by free‐radical polymerization with a monoacylphosphine oxide, (2,4,6‐trimethylbenzoyl) diphenylphosphine oxide (TPO), as a photoinitiator. Gel permeation chromatography (GPC) fractionation of the PS and PMMA samples with initial polydispersities of 1.81 and 2.81, respectively, yielded improved MALDI‐TOF MS spectra. Spectral analyses of the PS fractions showed distributions attributable to PS having two diphenylphosphinyl ends and PS having one diphenylphosphinyl end and/or one 2,4,6‐trimethylbenzoyl end, indicating that a combination of PS radicals with the highly reactive diphenylphosphine oxide group at one end of the chains was the predominant mode of termination. MALDI‐TOF MS results for PMMA fractions provided evidence for termination primarily by disproportionation, but structure determination was confounded by the presence of isobaric peaks. Discernible peaks were obtained by MALDI‐TOF MS analyses of GPC fractions of TPO‐initiated poly(methyl‐d3 methacrylate‐d5), in which the major product was PMMA with a diphenylphosphinyl end group and an abstracted deuterium end group, whereas the minor combination product had two diphenylphosphinyl chain ends. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2161–2171, 2007 [ABSTRACT FROM AUTHOR]

Hexagonal PdII- or CdII-tetrakispyridinyl-based macrocycles are quantitatively self-assembled from 4′-(3-pyridinyl)-4,4′′-di(tert-butyl)-2,2′ : 6′,2′′-terpyridine and structurally confirmed by NMR and TWIM-MS. [ABSTRACT FROM AUTHOR]