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Papers by Ali Shahrokhinia

Research paper thumbnail of Dynamic Worm-Gel Materials as Tunable, Regenerable Adsorbents for Water Treatment

Research paper thumbnail of Multi-responsive nanogels with tunable orthogonal reversible covalent (TORC) core-crosslinks for AND-gate controlled release

Polymer Chemistry, Dec 31, 2022

Research paper thumbnail of PhotoATRP-Induced Self-Assembly (PhotoATR-PISA) Enables Simplified Synthesis of Responsive Polymer Nanoparticles in One-Pot

Macromolecules, Jan 21, 2021

Photo-controlled atom transfer radical polymerization (PhotoATRP) was implemented, for the first ... more Photo-controlled atom transfer radical polymerization (PhotoATRP) was implemented, for the first time, to accomplish polymerization induced self-assembly (PISA) 1 mediated by UV light (λ = 365 nm) using ppm levels (ca. < 20 ppm) of copper catalyst at ambient temperature. Using Cu II Br 2 /tris(pyridin-2-ylmethyl)amine (TPMA) catalyst systems, PISA was performed all in one-pot starting from synthesis of solvophilic poly(oligo(ethylene oxide) methyl ether methacrylate) (POEGMA) blocks to core-crosslinked nanoparticles (NPs) utilizing poly(glycidyl methacrylate) (PGMA) and N,N-cystamine bismethacrylamide (CBMA) as the solvophobic copolymer and crosslinking agent, respectively. Sequential chain-extensions were performed for PGMA demonstrating capabilities for accessing multi-block copolymers with temporal control via switching the UV light on and off. Further, core-crosslinking of PISA nanoparticles was performed via the slow incorporation of the CBMA enabling one-pot crosslinking during the PISA process. Finally, the disulfide installed in the CBMA corecrosslinks allowed for the stimuli-triggered dissociation of nanoparticles using DL-dithiothreitol at acidic pH.

Research paper thumbnail of The effect of mixed and individual silane external donors on the stereo-defect distribution, active sites and properties of polypropylene synthesized with fourth generation Ziegler—Natta catalyst

Polymer Science Series A, 2015

Polypropylene was synthesized with a fourth generation of Ziegler—Natta catalyst and in the prese... more Polypropylene was synthesized with a fourth generation of Ziegler—Natta catalyst and in the presence of mixed and individual external donors, namely cyclohexyl dimethoxymethylsilane and dicyclopenthyl dimethoxysilane. A synergic effect on molecular weight and polydispersity index and changes in crystallinity and crystallization peak temperature with change in molar ratio of donor C to D were observed. The SSA results and related statistical parameters showed that in spite of close average stereo-regularity, the stereodefect distribution differences among the samples obtained with mixed external donors were so vast. The influence of mixed and individual external donors on active site distribution was studied and the results are discussed. The relationship between the crystallinity, molecular weight, stereo-defect distribution and dynamic and mechanical properties of samples was investigated.

Research paper thumbnail of Asymmetric Polymerization-Induced Crystallization-Driven Self-Assembly of Helical, Rod-Coil Poly(aryl isocyanide) Block Copolymers

Journal of the American Chemical Society, Mar 13, 2023

Research paper thumbnail of Asymmetric Polymerization-Induced Crystallization-Driven Self-Assembly of Helical, Rod-Coil Poly(Aryl Isocyanide) Block Copolymers

The helical motif is ubiquitous in naturally occurring chemical systems where it confers numerous... more The helical motif is ubiquitous in naturally occurring chemical systems where it confers numerous useful and distinct material properties. Accordingly, a great many synthetic materials have been produced in efforts to mimic biological systems. As an inherently chiral structural feature, the helix provides a modular platform for the creation of chiral nanomaterials exhibiting a diverse range of capabilities. Nonetheless, the development of rapid, scalable methods for production of chiral nanomaterials presents a formidable challenge. However, recent advances in both amphiphilic block copolymer (BCP) synthesis and self-assembly provide tractable means to do just that. In this work, polymerization induced crystallization-driven self-assembly (PI-CDSA) is combined, for the first time, with helical, rod-coil BCP self-assembly to enable scalable and controllable in situ synthesis of chiral nanostructures with variable shape, size, and dimensionality. Herein, we detail the use of newly dev...

Research paper thumbnail of Cover Image

Journal of Polymer Science, Aug 15, 2021

Research paper thumbnail of The relationship among changes in microstructure, active sites behavior and properties in the propylene polymerization with a 4th generation Ziegler-Natta catalyst

Three polypropylene samples (1-3) were synthesized with a 4th generation Ziegler-Natta catalyst i... more Three polypropylene samples (1-3) were synthesized with a 4th generation Ziegler-Natta catalyst in the presence of cyclohexyldimethoxymethylsilane (donor c), dicyclopenthyldimethoxysilane (donor d) and diisopropyldimethoxysilane (donor p), respectively, as external electron donors. The physical properties of the synthesized polypropylenes were determined. For samples 1 to 3, Successive self-nucleation and annealing (SSA) and Fourier transform infrared spectroscopy (FT-IR) analyses indicated that the relative content of the fraction with high isotacticity and regularity in conformational structure decreased in contrast with the fraction of low isotacticity and low uniformity in stereo-defect distribution from sample 1 to 3. The results demonstrated that the longer the isotactic sequence length and the less uniform the stereo-defect distribution, the greater the conformational order. Deconvolution of the molecular weight distribution curves indicated that the stability of the active c...

Research paper thumbnail of Chain Extensions in PhotoATRP-Induced Self-Assembly (PhotoATR-PISA): A Route to Ultrahigh Solids Concentrations and Click Nanoparticle Networks as Adsorbents for Water Treatment

Research paper thumbnail of Self-healing materials utilizing supramolecular interactions

Self-Healing Polymer-Based Systems

Research paper thumbnail of Orthogonal synthesis and modification of polymer materials

Journal of Polymer Science, 2021

Research paper thumbnail of Dynamic nanosphere networks (DNNs): A novel platform for regenerable adsorbents for point-of-use water treatment systems

Research paper thumbnail of PhotoATRP Induced Self-Assembly (PhotoATR-PISA) Enables Simplified Synthesis of Responsive Polymer Nanoparticles in One-Pot

ABSTRACT: Photo-controlled atom transfer radical polymerization (PhotoATRP) was implemented, for ... more ABSTRACT: Photo-controlled atom transfer radical polymerization (PhotoATRP) was implemented, for the first time, to accomplish polymerization induced self-assembly (PISA) mediated by UV light (λ = 365 nm) using ppm levels (ca. < 20 ppm) of copper catalyst at ambient temperature. Using CuIIBr2/tris(pyridin-2-ylmethyl)amine (TPMA) catalyst systems, PISA was per-formed all in one-pot starting from synthesis of solvophilic poly(oligo(ethylene oxide) methyl ether methacrylate) (POEGMA) blocks to core-crosslinked nanoparticles (NPs) utilizing poly(glycidyl methacrylate) (PGMA) and N,N-cystamine bismethacrylamide (CBMA) as the solvophobic copolymer and crosslinking agent, respectively. Sequential chain-extensions were performed for PGMA demonstrating capabilities for accessing multi-block copolymers with temporal control via switching the UV light on and off. Further, core-crosslinking of PISA nanoparticles was performed via the slow incorporation of the CBMA enabling one-pot crosslinki...

Research paper thumbnail of Dynamic Worm-Gel Materials as Tunable, Regenerable Adsorbents for Water Treatment

Research paper thumbnail of Multi-responsive nanogels with tunable orthogonal reversible covalent (TORC) core-crosslinks for AND-gate controlled release

Polymer Chemistry, Dec 31, 2022

Research paper thumbnail of PhotoATRP-Induced Self-Assembly (PhotoATR-PISA) Enables Simplified Synthesis of Responsive Polymer Nanoparticles in One-Pot

Macromolecules, Jan 21, 2021

Photo-controlled atom transfer radical polymerization (PhotoATRP) was implemented, for the first ... more Photo-controlled atom transfer radical polymerization (PhotoATRP) was implemented, for the first time, to accomplish polymerization induced self-assembly (PISA) 1 mediated by UV light (λ = 365 nm) using ppm levels (ca. < 20 ppm) of copper catalyst at ambient temperature. Using Cu II Br 2 /tris(pyridin-2-ylmethyl)amine (TPMA) catalyst systems, PISA was performed all in one-pot starting from synthesis of solvophilic poly(oligo(ethylene oxide) methyl ether methacrylate) (POEGMA) blocks to core-crosslinked nanoparticles (NPs) utilizing poly(glycidyl methacrylate) (PGMA) and N,N-cystamine bismethacrylamide (CBMA) as the solvophobic copolymer and crosslinking agent, respectively. Sequential chain-extensions were performed for PGMA demonstrating capabilities for accessing multi-block copolymers with temporal control via switching the UV light on and off. Further, core-crosslinking of PISA nanoparticles was performed via the slow incorporation of the CBMA enabling one-pot crosslinking during the PISA process. Finally, the disulfide installed in the CBMA corecrosslinks allowed for the stimuli-triggered dissociation of nanoparticles using DL-dithiothreitol at acidic pH.

Research paper thumbnail of The effect of mixed and individual silane external donors on the stereo-defect distribution, active sites and properties of polypropylene synthesized with fourth generation Ziegler—Natta catalyst

Polymer Science Series A, 2015

Polypropylene was synthesized with a fourth generation of Ziegler—Natta catalyst and in the prese... more Polypropylene was synthesized with a fourth generation of Ziegler—Natta catalyst and in the presence of mixed and individual external donors, namely cyclohexyl dimethoxymethylsilane and dicyclopenthyl dimethoxysilane. A synergic effect on molecular weight and polydispersity index and changes in crystallinity and crystallization peak temperature with change in molar ratio of donor C to D were observed. The SSA results and related statistical parameters showed that in spite of close average stereo-regularity, the stereodefect distribution differences among the samples obtained with mixed external donors were so vast. The influence of mixed and individual external donors on active site distribution was studied and the results are discussed. The relationship between the crystallinity, molecular weight, stereo-defect distribution and dynamic and mechanical properties of samples was investigated.

Research paper thumbnail of Asymmetric Polymerization-Induced Crystallization-Driven Self-Assembly of Helical, Rod-Coil Poly(aryl isocyanide) Block Copolymers

Journal of the American Chemical Society, Mar 13, 2023

Research paper thumbnail of Asymmetric Polymerization-Induced Crystallization-Driven Self-Assembly of Helical, Rod-Coil Poly(Aryl Isocyanide) Block Copolymers

The helical motif is ubiquitous in naturally occurring chemical systems where it confers numerous... more The helical motif is ubiquitous in naturally occurring chemical systems where it confers numerous useful and distinct material properties. Accordingly, a great many synthetic materials have been produced in efforts to mimic biological systems. As an inherently chiral structural feature, the helix provides a modular platform for the creation of chiral nanomaterials exhibiting a diverse range of capabilities. Nonetheless, the development of rapid, scalable methods for production of chiral nanomaterials presents a formidable challenge. However, recent advances in both amphiphilic block copolymer (BCP) synthesis and self-assembly provide tractable means to do just that. In this work, polymerization induced crystallization-driven self-assembly (PI-CDSA) is combined, for the first time, with helical, rod-coil BCP self-assembly to enable scalable and controllable in situ synthesis of chiral nanostructures with variable shape, size, and dimensionality. Herein, we detail the use of newly dev...

Research paper thumbnail of Cover Image

Journal of Polymer Science, Aug 15, 2021

Research paper thumbnail of The relationship among changes in microstructure, active sites behavior and properties in the propylene polymerization with a 4th generation Ziegler-Natta catalyst

Three polypropylene samples (1-3) were synthesized with a 4th generation Ziegler-Natta catalyst i... more Three polypropylene samples (1-3) were synthesized with a 4th generation Ziegler-Natta catalyst in the presence of cyclohexyldimethoxymethylsilane (donor c), dicyclopenthyldimethoxysilane (donor d) and diisopropyldimethoxysilane (donor p), respectively, as external electron donors. The physical properties of the synthesized polypropylenes were determined. For samples 1 to 3, Successive self-nucleation and annealing (SSA) and Fourier transform infrared spectroscopy (FT-IR) analyses indicated that the relative content of the fraction with high isotacticity and regularity in conformational structure decreased in contrast with the fraction of low isotacticity and low uniformity in stereo-defect distribution from sample 1 to 3. The results demonstrated that the longer the isotactic sequence length and the less uniform the stereo-defect distribution, the greater the conformational order. Deconvolution of the molecular weight distribution curves indicated that the stability of the active c...

Research paper thumbnail of Chain Extensions in PhotoATRP-Induced Self-Assembly (PhotoATR-PISA): A Route to Ultrahigh Solids Concentrations and Click Nanoparticle Networks as Adsorbents for Water Treatment

Research paper thumbnail of Self-healing materials utilizing supramolecular interactions

Self-Healing Polymer-Based Systems

Research paper thumbnail of Orthogonal synthesis and modification of polymer materials

Journal of Polymer Science, 2021

Research paper thumbnail of Dynamic nanosphere networks (DNNs): A novel platform for regenerable adsorbents for point-of-use water treatment systems

Research paper thumbnail of PhotoATRP Induced Self-Assembly (PhotoATR-PISA) Enables Simplified Synthesis of Responsive Polymer Nanoparticles in One-Pot

ABSTRACT: Photo-controlled atom transfer radical polymerization (PhotoATRP) was implemented, for ... more ABSTRACT: Photo-controlled atom transfer radical polymerization (PhotoATRP) was implemented, for the first time, to accomplish polymerization induced self-assembly (PISA) mediated by UV light (λ = 365 nm) using ppm levels (ca. < 20 ppm) of copper catalyst at ambient temperature. Using CuIIBr2/tris(pyridin-2-ylmethyl)amine (TPMA) catalyst systems, PISA was per-formed all in one-pot starting from synthesis of solvophilic poly(oligo(ethylene oxide) methyl ether methacrylate) (POEGMA) blocks to core-crosslinked nanoparticles (NPs) utilizing poly(glycidyl methacrylate) (PGMA) and N,N-cystamine bismethacrylamide (CBMA) as the solvophobic copolymer and crosslinking agent, respectively. Sequential chain-extensions were performed for PGMA demonstrating capabilities for accessing multi-block copolymers with temporal control via switching the UV light on and off. Further, core-crosslinking of PISA nanoparticles was performed via the slow incorporation of the CBMA enabling one-pot crosslinki...