Thermosensitive Block Copolymer Research Articles

Effect of Tannic Acid Concentrations on Temperature-Sensitive Sol-Gel Transition and Stability of Tannic Acid/Pluronic F127 Composite Hydrogels.

Recently, interest in polyphenol-containing composite adhesives for various biomedical applications has been growing. Tannic acid (TA) is a polyphenolic compound with advantageous properties, including antioxidant and antimicrobial properties. Additionally, TA contains multiple hydroxyl groups that exhibit biological activity by forming hydrogen bonds with proteins and biomacromolecules. Furthermore, TA-containing polymer composites exhibit excellent tissue adhesion properties. In this study, the gelation behavior and adhesion forces of TA/Pluronic F127 (TA/PluF) composite hydrogels were investigated by varying the TA and PluF concentrations. PluF (above 16 wt%) alone showed temperature-responsive gelation behavior because of the closely packed micelle aggregates. After the addition of a small amount of TA, the TA/PluF hydrogels showed thermosensitive behavior similar to that of PluF hydrogels. However, the TA/PluF hydrogels containing more than 10 wt% TA completely suppressed the thermo-responsive gelation kinetics of PluF, which may have been due to the hydrogen bonds between TA and PluF. In addition, TA/PluF hydrogels with 40 wt% TA showed excellent tissue adhesion properties and bursting pressure in porcine intestinal tissues. These results are expected to aid in understanding the use of mixtures of TA and thermosensitive block copolymers to fabricate adhesive hydrogels for versatile biomedical applications.

Exploiting PET-RAFT polymerization mediated by cross-linked zinc porphyrins for the thermo-sensitive regulation of poly(N-isopropylacrylamide-b-acrylamide)

A series of thermo-sensitive block copolymers poly(N-isopropylacrylamide-b-acrylamide) (P(NIPAm-b-AM)) are prepared via photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization mediated by the cross-linked zinc porphyrins (ZnTHP-Me2Si) with superior photo-catalytic properties using one-pot method. The thermal transition temperatures of P(NIPAm-b-AM) samples are analyzed via lower critical solution temperature (LCST) measurements in water/P(NIPAm-b-AM) mixtures, which show that the thermo-sensitive of P(NIPAm-b-AM) could be tuned by regulating the molar ratio of AM/NIPAm. Very interestingly, when the mole fraction of AM increased from 0 to 0.4, the LCST and water contact angle of P(NIPAm-b-AM) aqueous solution increased linearly, which means the thermo-sensitive polymers with target LCST or hydrophilicity could be prepared by increasing or decreasing AM content. In addition, the hardness of P(NIPAm-b-AM) also enhanced as the AM content increased. According to the density functional theory (DFT) calculations and radial distribution function (RDF) analyses, ZnTHP-Me2Si has smaller energy gap, and the H-bonding interaction between P(NIPAm-b-AM) and water molecules could be enhanced with increasing AM content. The outcomes of this work open new approaches to develop thermo-sensitive polymers with biocompatibility for the wide applications in highly efficient and controlled drug delivery system.

Multiresponsive Polymer Nanocomposite Liquid Crystals Having Heterogeneous Phase Transitions for Battery-Free Temperature Maintenance Indicators.

Multiresponsive functional materials that respond to more than one external stimulus are promising for novel photonic, electronic, and biomedical applications. However, the design or synthesis of new multiresponsive materials is challenging. Here, this work reports a facile method to prepare a multiresponsive colloidal material by mixing a liquid-crystalline 2D nanocolloid and a functional polymer colloid. For this purpose, electrically sensitive exfoliated α-ZrP 2D nanocolloids and thermosensitive block copolymer colloids that are dispersed well in water are mixed. In the liquid-crystalline nanocomposite, nematic, antinematic, or isotropic assemblies of α-ZrP, nanoparticles can be electrically and selectively obtained by applying electric fields with different frequencies; furthermore, their rheology is thermally and reversibly controlled through thesol-gel-sol transition. The nanocomposite exhibits a solid gel phase within a predesigned gel temperature range and a liquid sol phase outside this range. These properties facilitate the design of a simple display device in which information can be electrically written and thermally stabilized or erased, and using the device, a battery-free temperature maintenance indication function is demonstrated. The proposed polymer nanocomposite method can enrich the physical properties of 2D nanocolloidal liquid crystals and create new opportunities for eco-friendly, reusable, battery-free electro-optical devices.

Profiling target engagement and cellular uptake of cRGD-decorated clinical-stage core-crosslinked polymeric micelles

Polymeric micelles are increasingly explored for tumor-targeted drug delivery. CriPec® technology enables the generation of core‐crosslinked polymeric micelles (CCPMs) based on thermosensitive (mPEG-b-pHPMAmLacn) block copolymers, with high drug loading capacity, tailorable size, and controlled drug release kinetics. In this study, we decorated clinical-stage CCPM with the αvβ3 integrin-targeted cyclic arginine-glycine-aspartic acid (cRGD) peptide, which is one of the most well-known active targeting ligands evaluated preclinically and clinically. Using a panel of cell lines with different expression levels of the αvβ3 integrin receptor and exploring both static and dynamic incubation conditions, we studied the benefit of decorating CCPM with different densities of cRGD. We show that incubation time and temperature, as well as the expression levels of αvβ3 integrin by target cells, positively influence cRGD-CCPM uptake, as demonstated by immunofluorescence staining and fluorescence microscopy. We demonstrate that even very low decoration densities (i.e., 1 mol % cRGD) result in increased engagement and uptake by target cells as compared to peptide-free control CCPM, and that high cRGD decoration densities do not result in a proportional increase in internalization. In this context, it should be kept in mind that a more extensive presence of targeting ligands on the surface of nanomedicines may affect their pharmacokinetic and biodistribution profile. Thus, we suggest a relatively low cRGD decoration density as most suitable for in vivo application.Graphical

In situ insight into the self-assembly evolution of ABA-type block copolymers in water during the gelation process using infrared spectroscopy and near-infrared spectroscopy.

As a kind of thermo-responsive hydrogel, amphiphilic block copolymers are widely investigated. However, the molecular mechanism of their structural change during the gelation process is still limited. Here, a well-controlled triblock copolymer poly(N,N-dimethylacrylamide)-b-poly(diacetone acrylamide)-b-poly(N,N-dimethylacrylamide) (PDMAA-b-PDAAM-b-PDMAA) was synthesized. Its optical microrheology results suggest a gelation temperature range from 42 to 50 °C, showing a transition from viscosity to elasticity. The morphological transition from spheres to worms occurs. Temperature-dependent IR spectra through two-dimensional correlation spectroscopy (2D-COS) and the Gaussian fitting technique were analyzed to obtain the transition information of the molecular structure within the triblock copolymer. The N-way principal component analysis (NPCA) on the temperature-dependent NIR spectra was performed to understand the molecular interaction between water and the copolymer. The intramolecular hydrogen bonds within the hydrophobic PDAAM block tend to dissociate with temperature, resulting in improved hydration and a relative volume increase of the PDAAM block. The dissociation of intermolecular hydrogen bonds within the PDAAM block was the driving force for the morphological transition. Moreover, the hydrophilic PDMAA block dehydrates with temperature, and three stages can be found. The dehydration rate of the second stage with temperature from 42 to 50 °C was obviously higher than those in the lower (first stage) and higher (third stage) temperature ranges.

Effect of copolymer chain length and additives on the catalytic efficiency of thermo-sensitive block copolymer stabilized gold nanoparticles

The reduction of toxic 4-nitrophenol (4-NP) into non-toxic 4-aminophenol (4-AP) is an important reaction and gold nanoparticles (GNPs) have been explored for catalyzing this reduction process. In this work, three amphiphilic poly(N-isopropylacrylamide)-b-poly(styrene-r-vinyl pyridine) copolymers having different chain length was used to cap GNPs as well as gold nano rods (GNRs) and the catalytic efficiency of these polymer-GNP conjugates was evaluated for the reduction reaction in water. Thermosensitive conformational changes of these block copolymers in aqueous medium renders non-Arrhenius type temperature-dependent catalytic efficiency due to change in accessibility of GNP surface. The catalytic efficiency of GNPs was also influenced by the length of the coated polymers, shape of the gold nanoparticles and presence of salt or surfactant in the solution, which was also attributed to the altered accessibility of the reactants to the catalyst surface. Nearly no loss of catalytic activity and initial rate constant on recycling confirmed the stability of the polymer coating. Hence, these new catalysts could be potentially very useful in industrial applications.

Polymer nanomedicines based on micelle-forming amphiphilic or water-soluble polymer-doxorubicin conjugates: Comparative study of in vitro and in vivo properties related to the polymer carrier structure, composition, and hydrodynamic properties

The study compared the physico-chemical and biological properties of a water-soluble star-like polymer nanomedicine with three micellar nanomedicines formed by self-assembly of amphiphilic copolymers differing in their hydrophobic part (statistical, block and thermosensitive block copolymers). All nanomedicines showed a pH-responsive release of the drug, independent on polymer structure. Significant penetration of all polymer nanomedicines into tumor cells in vitro was demonstrated, where the most pronounced effect was observed for statistical- or diblock copolymer-based micellar systems. Tumor accumulation in vivo was dependent on the stability of the nanomedicines in solution, being the highest for the star-like system, followed by the most stable micellar nanomedicines. The star-like polymer nanomedicine showed a superior therapeutic effect. Since the micellar systems exhibited slightly lower systemic toxicity, they may exhibit the same efficacy as the star-like soluble system when administered at equitoxic doses. In conclusion, treatment efficacy of studied nanomedicines was directly controlled by the drug pharmacokinetics, namely by their ability to circulate in the bloodstream for the time needed for effective accumulation in the tumor due to the enhanced permeability and retention (EPR) effect. Easy and scalable synthesis together with the direct reconstitution possibility for nanomedicine application made these nanomedicines excellent candidates for further clinical evaluation.

A high efficiency method combining metal chelate ionic liquid-based aqueous two-phase flotation with two-step precipitation process for bromelain purification

This work was to develop a cost-effective and sustainable method which included metal chelate ionic liquid-based aqueous two-phase flotation (IL-based ATPF) and a two-step precipitation process for purifying bromelain from pineapple. Firstly, the metal chelate IL-based ATPF with a copper chelate-functionalized thermosensitive block copolymer (L64-IDA-Cu(II)) as trapping agent was used as the primary purification to obtain the L64-IDA-Cu(II)-bromelain complex. Secondly, the two-step precipitation process based on the thermosensitive properties of the L64-IDA-Cu(II) was mainly carried out to achieve the further purification of bromelain. According to a series of optimal experiments, the enzymatic activity recovery of final bromelain was 95.22 ± 0.04%, and the purification factor reached 6.56 ± 0.03. The results of recycling of ILs and the trapping agent were satisfactory. Furthermore, the conclusions of comparison with other methods proved the superiority of this method. This novel recycling purification method has a goodindustrial prospect in future.

Electrochemical dopamine sensor based on the use of a thermosensitive polymer and an nanocompositeprepared from multiwalled carbon nanotubes and graphene oxide.

An electrochemical dopamine sensor with a temperature-controlled switch was constructed by using a mixture of thermo-sensitive block copolymers (type tBA-PDEA-tBA), graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs). If the temperature is below 26°C, the polymer on the glassy carbon electrode (GCE) is stretched, the distance between the MWCNTs is large, and the charge transfer resistance (Rct) of the composite also is large. In the presence of dopamine, the electron transfer at theelectrode is strongly retarded and in the "off" state. At above 38°C, the polymer is shrunk and the Rct is much smaller. The presence of dopamine results in a rapid electron transfer at the GCE, and this is referred to as the "on" state. At temperatures between 26 and 38°C, the polymer shrinks slightly and has a "spring-like" state. There is a linear relationship between the response current (typically measured at a potential as low as 0.16V vs. Ag/AgCl) and temperature. The response to dopamine is linear in the 0.06 to 4.2μM and 4.2 to 18.2μM concentration range, and the detection limit is 42nM. Conceivably, this approach provides a novel approach towards the design of electrochemical sensors based on the use of thermo-sensitive polymers. Graphical abstract Schematic presentation of reversible and temperature-controlled electrochemical response of dopamine on the thermo-sensitive block copolymers (tBA-PDEA-tBA) / multi-walled carbon nanotubes (MWCNTs) / graphene oxide (GO) / glassy carbon electrode (GCE).

Composite of AuNPs@SiO $$_{2}$$ 2 NPs@[(NIPAM)- $${\varvec{b}}$$ b -(Ala)] and its activity on leukemia cells

Synthesis and characterization of thermo-sensitive block copolymer of N-isopropyl acryl amide-b-Alanine [(NIPAM)-b-(Alanine)] thin film and its doping with (AuNPs)–(\(\hbox {SiO}_{2}\hbox {NPs}\)), (gold and silica nanoparticles) were reported. Further, composite effect on K562 (leukemia) cells was examined based on in vitro cell-based studies. The synthesis of \(\hbox {SiO}_{2} \hbox {NPs}\) was followed through facile Stober’s sol–gel synthesis methods. The individual morphology of [(NIPAM)-b-(Alanine)] thin film, AuNPs and \(\hbox {SiO}_{2 }\)NPs including [(NIPAM)-b-(Alanine)]@(Au)-(\(\hbox {SiO}_{2} \hbox {NPs}\)) composite was confirmed by using TEM instrumentation. [(NIPAM)-b-(Alanine)] thin film was embedded with gold and silica nanoparticles followed by the sonication. The average size of AuNPs is 16 nm and for \(\hbox {SiO}_{2}\hbox {NPs}\), it is \({\sim }\)368 nm (in diameter). Synthesized composite [(NIPAM)-b-(Alanine)]@(Au)@(\(\hbox {SiO}_{2}\hbox {NPs}\)) is biocompatible for mankind use. However, composite used to examine the inhibitory activity on K562 cells and it shows \(\sim \)78% inhibition, which is significant value for 24 h treatment under humidified atmospheric conditions.

Preparation of a temperature-responsive block copolymer-anchored graphene oxide@ZnS NPs luminescent nanocomposite for selective detection of 2,4,6-trinitrotoluene

Thermo-sensitive block copolymer decorated GO@ZnS NPs nanocomposite was constructed via π–π stacking interaction as a robust fluorescent sensing platform for the selective detection of TNT.

Temperature- and Composition-Dependent DNA Condensation by Thermosensitive Block Copolymers.

Successful intracellular delivery of genes requires an efficient carrier, as genes by themselves cannot diffuse across cell membranes. Because of the toxicity and immunogenicity of viral vectors, nonviral vectors are gaining tremendous interest in research. In this work, we have investigated the temperature-dependent DNA condensation efficiency of various compositions of a thermosensitive block copolymer viz., poly(N-isopropylacrylamide)-b-poly(2-(diethylamino)ethyl methacrylate) (PNIPA-b-PDMAEMA). Three different copolymer compositions of varying molecular weights were successfully synthesized via the RAFT polymerization technique. Steady-state fluorescence and circular dichroism (CD) spectroscopies, dynamic light scattering (DLS) and zeta potential measurements, agarose gel electrophoresis, and atomic force microscopy techniques were utilized to study the interaction of the copolymers with DNA at temperatures above and below the critical aggregation temperature (CAT). All these experiments revealed that, above the CAT, there was formation of highly stable and tight polymer–DNA complexes (polyplexes). The size of polyplexes was dependent on the temperature up to a certain charge ratio, as determined by the DLS results. The results obtained from temperature-dependent fluorescence spectroscopy, CD, and gel electrophoresis indicated that the DNA molecules were shielded more from aqueous exposure above the CAT because of the formation of relatively more compact complexes. The polyplexes also exhibited changes in the particle morphology below and above the CAT, with particles generated above CAT being more spherical in morphology. These results suggested at the possibility of modulating the complex formation by temperature modification. The present biophysical studies would provide new physical insight into the design of novel gene carriers.

Thermosensitive block copolymer [(PNIPAM)-b-(Glycine)] thin film as protective layer for drug loaded mesoporous silica nanoparticles

Synthesis and characterization of [(PNIPAM)-b-(Gly)] and mesoporous silica nanoparticles (MP-SiO2 NPs) were carried out separately and used to develop [(PNIPAM)-b-(Gly)]-(MP-SiO2 NPs). The synthesized MP-SiO2 NPs were meso porous in nature. The size of SiO2 NPs is in the range of ~180–250 nm (in diameter) with an average pore size of 2.8 nm within the particles. Interestingly, these mesoporous SiO2 NPs were loaded with anticancer drug (ITM-imatinib mesylate) fallow by the incubation for 24 h at RT. However, ITM loaded MP-SiO2 NPs were capped or covered with synthesized [(PNIPAM)-b-(Gly)] thin film. Here, thin film acts as protective layer for drug loaded MP-SiO2 NPs, with that leakage of drug molecules throughout its transport pathway can be avoided. Significantly, thermosensitive [(PNIPAM)-b-(Gly)] polymer thin film depletes at body temperature (~37 °C) and drug molecules come out from the pores of SiO2 NPs. However, developed [(PNIPAM)-b-(Gly)]-(MP-SiO2 NPs) is compatible and used for cell inhibition studies. After 24 h treatment, drug ITM released from [(PNIPAM)-b-(Gly)]-(MP-SiO2 NPs) shows significant (>90%) inhibition on leukemia blood cancer (K562) cells.

Cucurbit[7]-assisted sustained release of human calcitonin from thermosensitive block copolymer hydrogel

Conventional formulations of human calcitonin (hCT), a peptide drug, normally suffer from limited therapeutic efficacy with low stability and short half-life. We have found that the fibrillation of highly amyloidogenic hCT can be inhibited by cucurbit[7] (CB[7]), an amphiphilic small molecule. Meanwhile, a thermogelling copolymer was found to be a suitable candidate for sustained delivery of peptide/protein drugs. Herein, we report a long-term delivery formulation composed of hCT-CB[7] complex and biodegradable thermogel of poly(D,L-lactic acid-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(D,L-lactic acid −co-glycolic acid) (PLGA-PEG-PLGA). A 20wt% PLGA-PEG-PLGA solution exhibited a temperature-sensitive sol-gel transition at 35°C in phosphate buffer solution and slowly degraded over one month at neutral pH. Both the mass fraction of PLGA-PEG-PLGA copolymer and the complexation of hCT-CB[7] moderated the release process. hCT was sustainedly released over three weeks in the 20wt% hydrogel with hCT-CB[7] complex at the ratio of 1:10 or 1:25. Further considering its low cytotoxicity, the delivery system is potential for the clinical application of hCT.

A novel type of responsive double hydrophilic block copolymer-based multifunctional fluorescence chemosensor and its application in biological samples

In this paper, a novel type of responsive double hydrophilic block copolymer (DHBC)-based multifunctional chemosensors to Al3+, Zn2+ and temperature was designed and prepared. The well-defined DHBCs with Al3+ and Zn2+-reactive thermosensitive block (copolymer fluorescence chemosensor), poly(ethylene oxide)-b-poly(N-isopropylacrylamide-co-SHMA)65(PEO113-b-P(NIPAM-co-SHMA)65, Mn=13.2kDa,Mw/Mn=1.09), were synthetized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The novel well water-soluble copolymer fluorescence chemosensor could selectively recognize Al3+ (blue fluorescence) and Zn2+ (green fluorescence) by the difference of the fluorescence color. Moreover, this copolymer fluorescence chemosensor has the ability to selective recognition Al3+ or Zn2+ in their mixed solution by controlling the fluorescence response time. The detection limit of 0.1g/L copolymer fluorescence chemosensor for the analysis of Al3+ and Zn2+ ions at 25°C were calculated to be ∼5.23 and ∼11.99ppb, respectively. PEO113-b-P(NIPAM-co-SHMA) can self-assemble into micelles with P(NIPAM-co-SHMA) block as core and well-solvated PEO block as coronas when heating to the lower critical solution temperature (LCST), and the detection limit of Al3+ and Zn2+ ions at 40°C can be decreased to ∼2.14 and ∼8.71ppb, respectively. Furthermore, the copolymer fluorescence chemosensor has been successfully applied to detect Al3+ and Zn2+ in biological samples.

Synthesis and properties of amphiphilic thermo-sensitive block copolymers

Octadecyl acrylate (ODA) as hydrophobic monomer and N-isopropylacryamide (NIPAAm) as hydrophilic monomer were chosen to synthetize the thermo-sensitive block copolymers PODAx-PNIPAAmy-PODAx (BAB-type) via reversible-addition-fragmentation chain transfer (RAFT) polymerization, the block copolymers could self-assemble to flower-like micelles in aqueous solution with hydrophobic PODA as the inner core and stabilized by hydrophilic PNIPAAm as the outer shell. The characterizations of the micelles such as surfactivity, thermo-sensitivity, micelle hydrodynamic radius (Rh) and polydispersity index (PdI) were demonstrated by surface tension technique, UV-Vis, and dynamic light scattering (DLS) measurements, respectively. The longer the hydrophilic chain was, the higher the critical micellization concentration (CMC) would be, and the higher content of the PODA was, the lower the lower critical solution temperature (LCST) would be. The average Rh remained at about 100 nm below LCST, but decreased sharply to about 42 nm and kept constant when reaching and above LCST, which meant the non-aggregation of BAB type block copolymers. The micelle was homogeneous with the small PdI within the range of research. B0.5mA24mB0.5m had the largest capacity to encapsulate lipophilic Sudan Red IV model drugs and the drug loading efficiency was 9.76%.

Small-angle X-ray scattering from the concentrated bulk phase separated from an amphiphilic block-copolymer solution

Aqueous solutions of the doubly thermosensitive block copolymer poly(2-isopropyl-2-oxazoline)-b-poly(2-ethyl-2-oxazoline) heated to 50 °C underwent a macroscopic liquid/liquid phase separation. The small-angle X-ray scattering intensity recorded from the concentrated phase settled on the bottom of a sample indicated that this phase was in the disordered state without any microphase separation, although the block copolymer was amphiphilic in water at 50 °C. It was also confirmed that the contribution to the scattering intensities of individual copolymer chains and their aggregates existing in the coexisting concentrated phase was very small, compared with the total scattering intensity of the phase-separated solution, when the concentrated phase was suspended in the form of colloidal droplets in the lean phase. The small-angle X-ray scattering intensity from the coexisting concentrated phase was measured in a phase-separated aqueous solution of the thermosensitive block copolymer poly(2-isopropyl-2-oxazoline)-b-poly(2-ethyl-2-oxazoline) under amphiphilic conditions (50 °C). The concentrated phase was disordered with no sign of micro phase separation. In addition, the scattering from individual copolymer chains and their aggregates existing in the concentrated phase hardly contributed to the total scattering intensity of the phase-separated colloidal solution of the block copolymer.

Synthesis of a phenylboronic acid-functionalized thermosensitive block copolymer and its application in separation and purification of vicinal-diol-containing compounds

Phenylboronic acid-functionalized PEO20PPO60PEO20 was synthesized and used to separate ortho-hydroxyl compounds as the collector in an aqueous two-phase flotation system.

Thermosensitive copolymer synthesized by controlled living radical polymerization: Phase behavior of diblock copolymers of poly(N‐isopropyl acrylamide) families

ABSTRACTIn this study, we prepared a series of thermosensitive polymers with low polydispersity index (PDI) values by nitroxide‐mediated controlled radical polymerization (NMRP) with 2,2,6,6‐tetramethyl‐1‐piperdinyloxy nitroxide (TEMPO) as a stable nitroxide‐free radical. Poly(N‐isopropyl acrylamide) (PNIPAAm)‐block‐poly(N‐tert‐butyl acrylamide) (PNTBA) was successfully synthesized, first, through polymerization with N‐isopropyl acrylamide to obtain the reactive polymer PNIPAAm‐TEMPO and, second, through polymerization by the addition of N‐tert‐butyl acrylamide (NTBA). The added molar fraction of NTBA during the second polymerization was adjusted accordingly to obtain the final polymerization product, a thermosensitive polymer (PNIPAAm‐block‐PNTBA), which had a targeted lower critical solution temperature (LCST). The result shows that the synthesis method used in this study effectively controlled the formation of the polymer to obtain a low PDI. The thermosensitive block copolymer, PNIPAAm‐b‐PNTBA (molar ratio = 9:1), with LCSTs in the range 27.7–39.8°C, was obtained through controlled living radical polymerization with PNIPAAm–TEMPO. Specifically, the 5 wt % aqueous solution of PNIPAAm‐b‐PNTBA (molar ratio = 9:1) had an LCST of 37.4°C; this was close to body temperature, 37°C. The 5 wt % aqueous solution of PNIPAAm‐b‐PNTBA (molar ratio = 9:1) showed potential for use in biomedical applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43224.

PhotoATRP-Based Fluorinated Thermosensitive Block Copolymer for Controllable Water/Oil Separation

The increasing environmental burden in human society calls for the development of more environmentally benign technologies and sustainable applications. Wastewater contaminated by oil or organic solvents has become a serious environmental issue nowadays. Herein, a well-defined thermosensitive block copolymer was designed and used for controllable water/oil separation. The functional material poly(2,2,3,4,4,4-hexafluorobutyl methacrylate)-block-poly(N-isopropylacrylamide) was synthesized through a new environmentally benign “living” radical polymerization technique [i.e., photoinitiated atom-transfer radical polymerization (photoATRP)]. The synthesized functional copolymer was considered as a modifier for fabricating a smart surface with thermal-responsive wettability. The switchable mechanism, surface composition, and morphology of the as-fabricated surface were investigated by water contact-angle measurement, X-ray photoelectron spectroscopy, and atomic force microscopy. Results showed that the as-fabric...