Thermoresponsive Block Copolymer Core–Shell Nanoparticles with Tunable Flow Behavior in Porous Media

Abstract

With the purpose of investigating new polymeric materials as potential flow modifiers for their future application in enhanced oil recovery (EOR), a series of amphiphilic poly(di(ethylene glycol) methyl ether methacrylate-co-oligo(ethylene glycol) methyl ether methacrylate) [P(DEGMA-co-OEGMA)]-based core–shell nanoparticles were prepared by aqueous reversible addition–fragmentation chain transfer-mediated polymerization-induced self-assembly. The developed nano-objects were shown to be thermoresponsive, demonstrating a reversible lower-critical solution temperature (LCST)-type phase transition with increasing solution temperature. Characterization of their thermoresponsive nature by variable-temperature UV–vis and dynamic light scattering analyses revealed that these particles reversibly aggregate when heated above their LCST and that the critical transition temperature could be accurately tuned by simply altering the molar ratio of core-forming monomers. Sandpack experiments were conducted to evaluate their pore-blocking performance at low flow rates in a porous medium heated at temperatures above their LCST. This analysis revealed that particles aggregated in the sandpack column and caused pore blockage with a significant reduction in the porous medium permeability. The developed aggregates and the increased pressure generated by the blockage were found to remain stable under the injection of brine and were observed to rapidly dissipate upon reducing the temperature below the LCST of each formulation. Further investigation by double-column sandpack analysis showed that the blockage was able to reform when re-heated and tracked the thermal front. Moreover, the rate of blockage formation was observed to be slower when the LCST of the injected particles was higher. Our investigation is expected to pave the way for the design of “smart” and versatile polymer technologies for EOR applications in future studies.

Dipeptide-Based Photoreactive Instant Glue for Environmental and Biomedical Applications

“…When the concentration of the compounds decreases, the solution remains liquid and becomes cloudier after curing (Figure S6b). Even though all the compounds are hydrophilic, we assume that insoluble cross-linked aggregates (nanogels) are formed in lower concentrations, decreasing the solution transparency . The SEM image with a 15% cross-linker molar ratio reveals a porous morphology for the dried glue after curing (Figure a).…”

“…Even though all the compounds are hydrophilic, we assume that insoluble cross-linked aggregates (nanogels) are formed in lower concentrations, decreasing the solution transparency. 42 The SEM image with a 15% cross-linker molar ratio reveals a porous morphology for the dried glue after curing (Figure 1a). The effect of the cross-linker's molar ratio on the morphology of the polymeric network is evident in Figure 1b, where the pore sizes are smaller when 45% molar ratio was used.…”

Preparation of functional nanoparticles of mPEG‐b‐P(DMA‐co‐HA) copolymers via polymerization‐induced thermal self‐assembly

“…Kempe and coworkers reported that the overall polymer hydrophobicity of graft copolymers could be increased by increasing the length of the side chains, thereby decreasing polymer LCST 28 . Several groups including Lutz, Hoth, Kostjuk, Georgiou, and ourselves, have previously reported that polymer LCST could be controlled by copolymerizing with a high LCST monomer with monomers of lower LCST 29–33 . Recent reports by our group have also shown that the thermoresponsive behavior of amphiphilic copolymers can be tuned by diversifying the hydrophobicity of comonomers in both brushy and linear copolymers 34 .…”

“…28 Several groups including Lutz, Hoth, Kostjuk, Georgiou, and ourselves, have previously reported that polymer LCST could be controlled by copolymerizing with a high LCST monomer with monomers of lower LCST. [29][30][31][32][33] Recent reports by our group have also shown that the thermoresponsive behavior of amphiphilic copolymers can be tuned by diversifying the hydrophobicity of comonomers in both brushy and linear copolymers. 34 In the case of linear polymers, it was also shown that the thermoresponsive behavior of the polymers could be correlated to their hydrophobicity.…”

Thermo-responsive block copolymers: assembly and application

“…In the former case, the thermo-responsive polymers become hydrophobic from the hydrophilic state in solvents as temperature increases, while in the latter case thermo-responsive polymers become hydrophilic from the hydrophobic state. In the current literature, LCST-type thermo-responsive polymers are mostly studied, which mainly include polyacrylamides, [63][64][65] polyethylene oxides, [66][67][68][69] polyacrylates [70][71][72][73] and polyimidazoles, 43,74,75 which can undergo phase transition in water, and their applications in biomedical 76,77 and wastewater treatment 4,43,58 are investigated. UCST-type thermo-responsive polymers are mainly amphiphilic polyelectrolytes, such as polysulfone betaines, 78,79 poly(N-acryloyl glycinamide) 27,80 and ionic polypeptides.…”