Stimuli-Responsive Y-Shaped Polymer Brushes Based on Junction-Point-Reactive Block Copolymers

Inspired by nature, stimuli-responsive systems were established andextensively developed in the past two to three decades. Among them, ever increasingattention has been paid to the field of responsive polymers due to their adjustablemolecular structure and polymorphism of morphologies. The recent advances inpolymer chemistry gave an impetus to the design of multi-responsive polymericmaterials that recognize independently or synergistically more than one stimulusexhibiting collective responses. Based on this principle, the main goal of this researchis the synthesis and study of the responsive behavior of triple stimuli-responsivehybrid Janus and micellar nanoparticles. The ability of these materials to alter theirphysico-chemical properties in response to multiple changes in their environmentalconditions renders them attractive candidates in a diverse range of applications.Hybrid Janus nanoparticles represent a new class of hybrid materials with aninorganic core and asymmetric grafting of polymer brushes from their surface. Thehigh demand for such particles contradicts their small-scale production methods. Inresponse to that, this work takes advantage of the large surface area provided byspherical polymer latex particles to immobilize silica nanoparticles at the latexsolventinterphase and thus provide shielding to one hemisphere of the colloidal silicananoparticles embedded in the latex particles, whereas the exposed silica surface canbe chemically modified as required. Here, the exposed surface of the silicananoparticles was functionalized with atom transfer radical polymerization (ATRP)initiating sites. These asymmetric functionalized nanoparticles were used for thegrowth of a hydrophobic polymer poly(methyl methacrylate) (PMMA); ahydrophobic polymer, poly(tert-butyl acrylate) (Pt-BA) that can be hydrolyzed toform an anionic and pH-responsive derivative poly(acrylic acid) (PAA); and ahydrophilic, cationic and pH- and temperature-responsive polymer, poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA). For comparison, the fully-coatednanoparticle analogues were also synthesized employing the same polymerizationconditions. The successful grafting of the polymers from the surface of the silicananoparticles was verified by TGA, while high molecular weight polymers of narrowmolecular weight distributions were measured by GPC, verifying the control of thesurface-initiated polymerization reactions. Observation by FESEM provided insight on the topology of the hybrid Janus nanoparticles, suggesting the formation of acornlikenanoparticles. The aqueous solution behavior of the Janus and fully-coatedPDMAEMA and PAA nanoparticles were investigated by DLS, potentiometrictitrations and zeta potential measurements verifying the responsive behavior of thenanoparticles. Additionally, well-defined amphiphilic hybrid Janus nanoparticlescomprising an inorganic silica core and a shell consisting of compartmentalized PAAand PDMAEMA chains were synthesized via a multi-step ATRP surface-initiatedpolymerization process. The successful grafting of the polymer brushes on theopposite hemispheres of the nanoparticles was evidenced by TGA, whereas highmolecular weight and narrow molecular weight distributions were measured for bothpolymers. The ampholytic hybrid Janus nanoparticles exhibited a pH-responsivebehavior in aqueous solution due to the presence of both ionizable, DMAEMA andAA, groups on the nanoparticles‟ surface. DLS studies showed a variation of thehydrodynamic diameter of the polyamholytic hybrid nanoparticles as a function ofsolution pH. At the extreme pH values the size of the nanoparticles reached amaximum, while near the isoelectric point the nanoparticles‟ size collapsed.In the second part of this work, hybrid Janus nanoparticles that respond tochanges of the solution pH and temperature and to light irradiation were synthesized.For their synthesis, DMAEMA and the in-house synthesized monomer, 1',3',3'-trimethyl-6-methacryloyloxy-spiro(2H-1-benzopyran-2,2'-indoline) (SPMA) werecopolymerized from the surface of Janus initiator nanoparticles by surface-initiatedATRP. Two hybrid Janus nanoparticles were synthesized bearing 3 and 15 mole %SPMA, respectively. The pH- thermo- and light-responsive behavior of the SiO2-g-(PDMAEMA-co-PSPMA) hybrid Janus nanoparticles bearing 15 mole % SPMA wasinvestigated in water by UV/Vis and DLS studies, verifying the triple-responsivebehavior of the nanoparticles.Finally, multi-responsive block copolymers were synthesized by the sequentialATRP of DMAEMA followed by the polymerization of the in-house synthesizedmonomer SPMA. Two block copolymers were synthesized bearing 3 and 14 mole %SPMA, respectively. The PDMAEMA-b-PSPMA block copolymers can selfassembleinto well-defined spherical micelles, comprising a hydrophobic PSPMAcore and a hydrophilic PDMAEMA shell, in aqueous solution. The responsivebehavior of the micelles when applying three different stimuli (i.e. light, pH and temperature) was verified, while their capability to encapsulate a model compoundand release it in response to UV light irradiation was also investigated.

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Multi-Stimuli-Responsive Mesoporous Membranes and Effect of Molecular Architecture on Thermo- and pH-Responsive Behavior of the grafted Block Copolymer brushes

10.26434/chemrxiv.7037699 ◽

2019 ◽

Author(s):

Yanchun Tang ◽

Kohzo Ito ◽

Hideaki Yokoyama

Keyword(s):

Polymer Brushes ◽

Diblock Copolymers ◽

Neutron Reflectivity ◽

Molecular Architecture ◽

Stimuli Responsive ◽

Responsive Polymer ◽

The Matrix ◽

Stable Part ◽

Copolymer Brushes ◽

Mesoporous Membranes

In this study, we prepared ultrafiltration membranes with a decoupled responses of filtration property to temperature and pH. The membrane preparation method was developed based on our previous work. We utilized methanol-supercritical carbon dioxide (methanol-scCO2) selective swelling method to introduce nanopores to block copolymers containing poly(diethylene glycol) methyl ether methacrylate (PMEO2MA), poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) and polystyrene (PS) blocks. Formation of the mesoporous barrier layer with PS being the mechanically stable part of the matrix was driven by selective swelling of the PMEO2MA-b-PDMAEMA domains. Due to the selective swelling of PMEO2MA or PDMAEMA domains to introduce pores, the interior of the pores are covered with PMEO2MA or PDMAEMA blocks after pore formation. The PMEO2MA-b-PDMAEMA polymer brushes are naturally attached on the pore walls and worked as functional gates. PMEO2MA is a non-toxic, neutral thermo-responsive polymer with LCST at 26 ᴼC. PDMAEMA is a typical weak polyelectrolyte with pKa value at 7.0-7.5 and also a thermo-responsive polymer revealed a LCST of 20-80 °C in aqueous solution. Therefore, these membranes were expected to have multi dimensions as function of the combination of temperature and pH. Moreover, to understand the detail of the temperature and pH depended conformation transitions of PMEO2MA-b-PDMAEMA brushes, those diblock copolymers were end-tethered on flat substrates and analyzed via neutron reflectivity (NR).

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Polymerisation-induced self-assembly (PISA) as a straightforward formulation strategy for stimuli-responsive drug delivery systems and biomaterials: recent advances

Biomaterials Science ◽

10.1039/d0bm01406k ◽

2021 ◽

Vol 9 (1) ◽

pp. 38-50

Author(s):

Hien Phan ◽

Vincenzo Taresco ◽

Jacques Penelle ◽

Benoit Couturaud

Keyword(s):

Drug Delivery ◽

Block Copolymers ◽

Drug Release ◽

Self Assembly ◽

Drug Delivery Systems ◽

Amphiphilic Block Copolymers ◽

Stimuli Responsive ◽

Site Specific ◽

On Demand ◽

Redox Agents

Stimuli-responsive amphiphilic block copolymers obtained by PISA have emerged as promising nanocarriers for enhancing site-specific and on-demand drug release in response to a range of stimuli such as pH, redox agents, light or temperature.

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Conformation Study of Dual Stimuli-Responsive Core-Shell Diblock Polymer Brushes

Polymers ◽

10.3390/polym10101084 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1084

Author(s):

Kaimin Chen ◽

Lan Cao ◽

Ying Zhang ◽

Kai Li ◽

Xue Qin ◽

...

Keyword(s):

Polymer Brushes ◽

Core Shell ◽

Stimuli Responsive ◽

Research Topics ◽

Design And Synthesis ◽

Mild Conditions ◽

The Core ◽

Responsive Polymer ◽

Stimuli Responsive Polymer ◽

Shed Light

Stimuli-responsive nanoparticles are among the most popular research topics. In this study, two types of core-shell (polystyrene with a photoiniferter (PSV) as the core and diblock as the shell) polymer brushes (PSV@PNIPA-b-PAA and PSV@PAA-b-PNIPA) were designed and prepared using surface-initiated photoiniferter-mediated polymerization (SI-PIMP). Moreover, their pH- and temperature-stimuli responses were explored by dynamic light scattering (DLS) and turbidimeter under various conditions. The results showed that the conformational change was determined on the basis of the competition among electrostatic repulsion, hydrophobic interaction, hydrogen bonding, and steric hindrance, which was also confirmed by protein adsorption experiments. These results are not only helpful for the design and synthesis of stimuli-responsive polymer brushes but also shed light on controlled protein immobilization under mild conditions.

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Thermoswitchable Janus Gold Nanoparticles with Stimuli-Responsive Hydrophilic Polymer Brushes

Langmuir ◽

10.1021/acs.langmuir.6b00562 ◽

2016 ◽

Vol 32 (17) ◽

pp. 4297-4304 ◽

Cited By ~ 13

Author(s):

Xiaoqin Niu ◽

Fen Ran ◽

Limei Chen ◽

Gabriella Jia-En Lu ◽

Peiguang Hu ◽

...

Keyword(s):

Gold Nanoparticles ◽

Polymer Brushes ◽

Hydrophilic Polymer ◽

Stimuli Responsive

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Effect of Structure of Polymers Grafted from Graphene Oxide on the Compatibility of Particles with a Silicone-Based Environment and the Stimuli-Responsive Capabilities of Their Composites

Nanomaterials ◽

10.3390/nano10030591 ◽

2020 ◽

Vol 10 (3) ◽

pp. 591 ◽

Cited By ~ 2

Author(s):

Monika Zygo ◽

Miroslav Mrlik ◽

Marketa Ilcikova ◽

Martina Hrabalikova ◽

Josef Osicka ◽

...

Keyword(s):

Molecular Weight ◽

Graphene Oxide ◽

Radical Polymerization ◽

Polymer Brushes ◽

Silicone Oil ◽

Polymer Chains ◽

Butyl Methacrylate ◽

Raman Shift ◽

Stimuli Responsive ◽

Grafted Polymer

This study reports the utilization of controlled radical polymerization as a tool for controlling the stimuli-responsive capabilities of graphene oxide (GO) based hybrid systems. Various polymer brushes with controlled molecular weight and narrow molecular weight distribution were grafted from the GO surface by surface-initiated atom transfer radical polymerization (SI-ATRP). The modification of GO with poly(n-butyl methacrylate) (PBMA), poly(glycidyl methacrylate) (PGMA), poly(trimethylsilyloxyethyl methacrylate) (PHEMATMS) and poly(methyl methacrylate) (PMMA) was confirmed by thermogravimetric analysis (TGA) coupled with online Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Various grafting densities of GO-based materials were investigated, and conductivity was elucidated using a four-point probe method. Raman shift and XPS were used to confirm the reduction of surface properties of the GO particles during SI-ATRP. The contact angle measurements indicated the changes in the compatibility of GOs with silicone oil, depending on the structure of the grafted polymer chains. The compatibility of the GOs with poly(dimethylsiloxane) was also investigated using steady shear rheology. The tunability of the electrorheological, as well as the photo-actuation capability, was investigated. It was shown that in addition to the modification of conductivity, the dipole moment of the pendant groups of the grafted polymer chains also plays an important role in the electrorheological (ER) performance. The compatibility of the particles with the polymer matrix, and thus proper particles dispersibility, is the most important factor for the photo-actuation efficiency. The plasticizing effect of the GO-polymer hybrid filler also has a crucial impact on the matrix stiffness and thus the ability to reversibly respond to the external light stimulation.

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Self-assembly of stimuli-responsive block copolymers in aqueous solutions: an overview

Polymer Bulletin ◽

10.1007/s00289-019-03046-w ◽

2019 ◽

Vol 77 (11) ◽

pp. 5783-5810 ◽

Cited By ~ 1

Author(s):

Mehul Khimani ◽

Hiren Patel ◽

Vijay Patel ◽

Paresh Parekh ◽

Rohit L. Vekariya

Keyword(s):

Block Copolymers ◽

Aqueous Solutions ◽

Self Assembly ◽

Stimuli Responsive

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Stimuli-Responsive Semi-Fluorinated Polymer Brushes on Porous Silica Substrates

Macromolecular Rapid Communications ◽

10.1002/marc.200400193 ◽

2004 ◽

Vol 25 (14) ◽

pp. 1298-1302 ◽

Cited By ~ 45

Author(s):

Anthony M. Granville ◽

William J. Brittain

Keyword(s):

Polymer Brushes ◽

Porous Silica ◽

Stimuli Responsive ◽

Fluorinated Polymer ◽

Silica Substrates

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Conjugated rod–coil block copolymers: Synthesis, morphology, photophysical properties, and stimuli-responsive applications

Progress in Polymer Science ◽

10.1016/j.progpolymsci.2010.07.008 ◽

2011 ◽

Vol 36 (5) ◽

pp. 603-637 ◽

Cited By ~ 138

Author(s):

Cheng-Liang Liu ◽

Chia-Hung Lin ◽

Chi-Ching Kuo ◽

Sung-Tso Lin ◽

Wen-Chang Chen

Keyword(s):

Block Copolymers ◽

Photophysical Properties ◽

Stimuli Responsive

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Synthesis of ‘living’ poly(2-dimethylaminoethyl methacrylate) and stimuli responsive/multifunctional block copolymers effective in fabrication of CdS ‘smart’ ‘Q-Particles’

Polymer ◽

10.1016/j.polymer.2018.09.013 ◽

2018 ◽

Vol 155 ◽

pp. 27-41

Author(s):

Udayan Basak ◽

Radhakanta Ghosh ◽

Tapas Ghosh ◽

Soumabrata Majumdar ◽

Mahuya Pakhira ◽

...

Keyword(s):

Block Copolymers ◽

Stimuli Responsive ◽

Dimethylaminoethyl Methacrylate

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