Evaluation of the Interaction Parameter for Poly(solketal methacrylate)-block-polystyrene Copolymers

Abstract

A series of symmetric poly­(solketal methacrylate-b-styrene) (PSM-b-PS) copolymers with varying molecular weights that can transform a hydrophobic PSM block to a hydrophilic poly­(glycerol monomethacrylate) (PGM) block through an acid hydrolysis were investigated. This simple chemical transformation significantly enhances the segmental interaction parameter (χ), enabling a phase-mixed block copolymer (BCP) to microphase separate without any additives. Temperature-dependent small-angle X-ray scattering (SAXS) measurements as a function of the degree of polymerization (16 ≤ N ≤ 316) and PSM hydrolysis conversion were conducted to characterize the order-to-disorder transition (ODT) behavior as well as the lamellar microdomain features. Using a mean-field correlation-hole analysis of the scattering, the χ value for PSM and PS was determined as a function of the conversion of PSM to PGM. For 100% conversion of PSM to PGM, the χ with PS was found to be given by χ = 0.3144 + 36.91/T, with χ = 0.438 at 25 °C, which is ∼13 times larger in magnitude than χ parameter for PSM-b-PS copolymer (∼0.035 at 25 °C) calculated using a 118 Å3 reference volume. With this large increase in χ, even the smallest synthesized PGM-b-PS copolymers underwent microphase separation, allowing us to achieve a center-to-center lamellar microdomain spacing (commonly referred to as the full pitch) of 5.4 nm, obtained for the lowest molecular weight sample (M n = 2200 g/mol, N = 16).

Synthesis of High Molecular Weight Poly(glycerol monomethacrylate) via RAFT Emulsion Polymerization of Isopropylideneglycerol Methacrylate

“… 88 Indeed, the industrial manufacture of GMA monomer is achieved via acid-catalyzed deprotection of IPGMA, 27 and Hoogeveen et al reported the preparation of PGMA-based diblock copolymers from PIPGMA-based precursors via acid hydrolysis at ambient temperature for 72 h. 89 Very recently, Russell and co-workers reported the deprotection of IPGMA residues in a series of polystyrene–PIPGMA (PS–PIPGMA) diblock copolymers using HCl in 1,4-dioxane. 90 Of particular relevance to the present study, a similar strategy was recently utilized by Rimmer and co-workers for the synthesis of sterically stabilized PS–PGMA latexes from precursor core–shell PS–PIPGMA particles. 73 In this case, acid hydrolysis was conducted in aqueous solution at approximately pH 1 for 4–8 h at 60 °C, but no kinetic studies of the extent of deprotection were reported.…”

Poly(glycidyl methacrylate)/bacterial cellulose nanocomposites: Preparation, characterization and post-modification

“…glyceryl methacrylate. Alternatively, PGOHMA can be prepared by the acid-catalysed hydrolysis of precursor polymers, including poly(solketal methacrylate) [47,48]. Nevertheless, the acidcatalysed hydrolysis of PGMA [23,49] is a less expensive pathway due to the commercial availability of GMA [21].…”

Isoporous Membranes from Novel Polystyrene-b-poly(4-vinylpyridine)-b-poly(solketal methacrylate) (PS-b-P4VP-b-PSMA) Triblock Terpolymers and Their Post-Modification

“…It has also been reported as a material for ultrafiltration barriers mimicking the natural membranes in kidneys [43]. Poly(isopropylidene glycerol methacrylate), commonly known as poly(solketal methacrylate), is one of those polymers not yet studied widely in the context of block copolymer membranes produced via the SNIPS process [44][45][46][47]. Recently, we reported a detailed comparison of double hydrophobic PS-b-PSMA and amphiphilic PS-b-PGMA diblock copolymer membranes, where the influence of the hydrophobic or hydrophilic nature of the second block was analyzed by water flux and contact angle measurements.…”