Synthesis, molecular, and morphological characterization of initial and modified diblock copolymers with organic acid chloride derivatives

Abstract

Six well defined PS-b-PB 1,2 diblock copolymers (PS: polystyrene and PB: polybutadiene) with almost 100% of 1,2 microstructure for the PB segment were synthesized. Size exclusion chromatography (SEC), membrane osmometry (MO) and proton nuclear magnetic resonance spectroscopy (1 H NMR) were used for verification of the molecular characteristics and the 100%-1,2 addition for the PB blocks. Modification with heptanoyl or pentadecafluorooctanoyl chloride was accomplished via hydroboration and subsequent oxidation, leading to hydroxylated PB blocks and was verified with 1 H NMR and Fourier transform infrared (FTIR) spectroscopy. Only two samples were modified with both organic acid chloride derivatives. Structural characterization was accomplished via transmission electron mi-croscopy (TEM) and small-angle X-ray scattering (SAXS) in all cases. The self-assembly was more evident in the modified copolymers with the corresponding halides due to the increase of the molecular weight of the modified PB block. Taking into consideration the vN values in each case and comparing the results with those of PS-b-PI copolymers already reported in the literature the discrepancies with the theoretical predictions are very small or minimal. V

Nanoindentation of Films of Perfluorotridecyl, Perfluorodecyl, and Perfluoroheptyl End‐Functionalized Polystyrene at the Micron Scale

“…This polymer has been shown to exist in four different helical crystalline states I–IV, depending on temperature and pressure and appears to be susceptible to rapid helix reversals at elevated temperatures . In agreement with the above, numerous polymers containing RF pendent‐ or end groups have been shown to exhibit mesogenic properties . In addition perfluorocarbons and RF groups have been shown to give exceptionally low‐surface free energies .…”

Modified Diblock Copolymer Bearing Fluoro Groups and Evaluation of its Hydrophobic Properties

“…Its modification, synthesis and molecular characteristics (GPC & 1 H-NMR) have already been reported in the literature. [16] It was very crucial to obtain almost exclusively 1,2-microstructure in the PB segment, since it is necessary to achieve the maximum modification with fluorocarbon groups.…”

“…With increased solubility and adhesion the surface chemistry can be prominently understood and controlled. [16] The major scope of this manuscript is to evaluate hydrophobicity of a fluorinated modified diblock copolymer and to study the topography of the surface through various techniques such as SEM, AFM and contact angle measurements.…”

Exploring the Self-Assembly Capabilities of ABA-Type SBS, SIS, and Their Analogous Hydrogenated Copolymers onto Different Nanostructures Using Atomic Force Microscopy

“…The formation of well-ordered morphologies is mainly governed by the Flory–Huggins interaction parameter χ and the polymerization degree N (different χN values leading to morphologies that can be predicted through phase diagrams), together with other parameters such as the volume fraction of blocks and interfacial interactions [ 9 , 10 ]. Changes in N or χ parameters (block structure or nature) in block copolymers can alter obtained morphologies leading to new phase diagrams [ 11 , 12 ].…”

“…Triblock copolymers of poly(styrene-b-butadiene-b-styrene) (SBS) and poly(styrene-b-isoprene-b-styrene) (SIS) are polymers that are widely used in various applications, such as in modified asphalt for studying the physical and rheological properties of asphalt during aging (SBS as the main component) [ 54 ], or to study their viscoelastic behavior (in the case of SIS) [ 55 ]. The PB or PI as one of the blocks has a double bond that is easy to modify, creating new polymeric blocks with new properties for new applications [ 11 , 12 , 56 ]. In addition, these triblock copolymers can form different nanostructures (cylindrical, cubic bicontinuous, and lamellae) depending on their molecular weight, the sequence of the blocks, and their volume fraction.…”