Co-reporter:Xian’e Li, Zhi Xu, Hongyao Yin, Yujun Feng, and Hongping Quan
Energy & Fuels March 16, 2017 Volume 31(Issue 3) pp:2479-2479
Publication Date(Web):February 15, 2017
DOI:10.1021/acs.energyfuels.6b02653
High-molecular-weight polyacrylamide (PAM) has been widely used in chemically enhanced oil recovery (EOR) processes under mild conditions, but its poor tolerance to high temperature and high salinity impeded the use in severe oil reservoirs. To overcome the inadequacies of PAM, thermoviscosifying polymers (TVPs) whose viscosity increases upon increasing temperature and salinity were developed in recent years. In this work, comparative studies with PAM and TVP, having more similar molecular weights, were performed with regard to their rheological behaviors, thermal stability, and core flooding feasibility. It was found that the TVP aqueous solution exhibited thermothickening ability, even at a polymer concentration of 0.2 wt % with a total dissolved solids ratio (TDS) of 101 000 mg L–1 upon increasing temperature, while PAM only showed a monotonic decrease in viscosity under identical conditions. Remaining viscosity of TVP was higher than that of PAM after aging at 45 or 85 °C for one month. Core flooding tests demonstrated both polymers show good transportation in porous media, and a higher oil recovery of 16.4% and 15.5% can be attained by TVP at 45 and 85 °C, respectively, while those of PAM are only 12.0% and 9.20%.
Co-reporter:Xin Song;Hongyao Yin;Sheng Zhang;Yong Wang
Industrial & Engineering Chemistry Research June 15, 2016 Volume 55(Issue 23) pp:6563-6568
Publication Date(Web):2017-2-22
DOI:10.1021/acs.iecr.6b00836
In oil industry, wax deposition is one of the frequently encountered problems that causes severe issues during the production, storage, and transportation of crude oil. Recently, it is found that addition of nanohybrids to crude oil is an effective method to solve this problem. However, the mechanism of how nanoparticles affect the wax crystallization and rheological behavior of crude oil has not been clearly understood. Here we reported the influence of SiO2 nanoparticles on crystallization and rheological behavior of model oils with and without asphaltene and resin. It was demonstrated that the wax appearance temperature increased upon the addition of SiO2 nanoparticles of model oil without asphaltenes and resin, while the rheological behavior was less affected. When in the presence of asphaltenes and resin, the amount of wax crystals, wax appearance temperature, and rheological parameter of model oils were found to decrease while SiO2 nanofluid was added, resulting in the improvement of flowability.
Co-reporter:Hanbin Liu;Shaojian Lin;Patrick Theato
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 1) pp:12-23
Publication Date(Web):2016/12/20
DOI:10.1039/C6PY01101B
CO2-Responsive polymer materials have received enormous attention in recent years, since CO2 as a new trigger has many advantages such as abundant availability, low cost, energy-saving, environment-friendly, non-toxic, good reversibility as well as great biocompatibility. In this review, we first discuss the virtues of CO2-responsiveness by comparing with traditional stimuli-sensitive materials that respond to pH, light, or redox stimuli. Then, the chemical fundamentals of CO2-responsive polymer materials are revealed including recently discovered “unexpected” CO2-sensitive features. Recent progress of CO2-responsive polymer materials is highlighted followed by various CO2-responsive “smart” polymer systems. Finally, challenges and outlooks in this area are discussed.
Co-reporter:Ji Wang;Niti R. Agrawal;Srinivasa R. Raghavan
Physical Chemistry Chemical Physics 2017 vol. 19(Issue 36) pp:24458-24466
Publication Date(Web):2017/09/20
DOI:10.1039/C7CP04962E
Wormlike micelles (WLMs) formed from surfactants have attracted much attention for their ability to thicken water in a manner similar to water-soluble polymers. It is known that WLMs are cylindrical filaments that can attain very long contour lengths (∼few μm), akin to chains of polymers with ultra-high molecular weights (UHMWs). In this study, we aim to make a direct comparison between the thickening capabilities of WLMs and UHMW polymers. The chosen surfactant is erucyl dimethyl amidopropyl betaine (EDAB), a C22-tailed zwitterionic surfactant known to form particularly long WLMs independent of salt. The chosen polymer is nonionic polyacrylamide (PAM) having an UHMW of 12 MDa. Both EDAB WLMs and the PAM show strong thickening capability in saline water at 25 °C, but the WLMs are more efficient. For example, a 1.0 wt% EDAB WLM sample has a similar zero-shear viscosity η0 (∼40 000 mPa s) to a 2.5 wt% PAM solution. When temperature is increased, both samples show an exponential reduction in viscosity, but the WLMs are more sensitive to temperature. Microstructural differences between the two systems are confirmed by data from small-angle neutron scattering (SANS) and cryo-transmission electron microscopy (cryo-TEM). As expected, the key differences are that the WLM chains have a larger core radius (Rcore) and in turn, a longer persistence length (lp) than the PAM chains.
Co-reporter:Zanru Guo;Hongjian Gu;Wei Ma;Qiang Chen;Zhanfeng He;Jiali Zhang;Yongxin Liu;Longzhen Zheng
RSC Advances (2011-Present) 2017 vol. 7(Issue 78) pp:49777-49786
Publication Date(Web):2017/10/20
DOI:10.1039/C7RA09233D
The design of controllable or “signal-triggered” metal nanoparticles is one of the emerging trends in nanotechnology and advanced materials. CO2-switchable polymer-hybrid silver nanoparticles (AgNPs) were prepared by a one-pot reaction reducing AgNO3 and trithioester terminated PDEAEMA with sodium borohydride (NaBH4). The hybrids showed a long-term stability, and their size and size distribution can be easily modulated by tuning the molar ratio of polymers to AgNO3. The hybrids not only exhibit hydrophobic–hydrophilic transitions in immiscible mixed solvents, but also undergo a switchable dispersion/aggregation states upon alternately treating with CO2 and N2. Moreover, this smart hybrid was preliminarily used as catalyst for the reduction of 4-nitrophenol. The catalytic activity of the hybrids can be switched and monotonously tuned by varying the flow rate of CO2 purged into the reaction system, which may open a new avenue for tailoring the catalytic activity of metal nanoparticles toward a given reaction.
Co-reporter:Zanru Guo;Wei Ma;Hongjian Gu;Zhanfeng He;Qiang Chen;Xi Mao;Jiali Zhang;Longzhen Zheng
Soft Matter (2005-Present) 2017 vol. 13(Issue 40) pp:7371-7380
Publication Date(Web):2017/10/18
DOI:10.1039/C7SM00916J
Stimuli-responsive hydrogels using dynamic covalent bonds (DCBs) as cross-links may exhibit simultaneously the stimuli-responsibility of the physical gels and stability of the chemical gels. We prepared well-defined, ketone-based polymers based on commercially available diacetone acrylamide (DAAM) by a reversible addition–fragmentation chain transfer (RAFT) polymerization technique. The polymers could react with hexanedihydrazide yielding hydrogels. The mechanics, flexible properties and gelator concentration of the hydrogels can be tuned by varying the ratio of DAAM. Gelation time and hydrogel stability were gravely affected by the pH of the surrounding medium. The hydrogels possess self-healing ability without any external stimuli and undergo switchable sol–gel transition by the alternation of pH. In addition, the hydrogels showed pH-responsive controlled release behavior for rhodamine B. These kinds of ketone-type acylhydrazone DCB hydrogels, avoiding the aldehyde component, may ameliorate their biocompatibility and find potential applications in biomedicines, tissue engineering, etc.
Co-reporter:Yongmin Zhang, Yuandi Zhang, Cheng Wang, Xuefeng Liu, Yun Fang and Yujun Feng
Green Chemistry 2016 vol. 18(Issue 2) pp:392-396
Publication Date(Web):21 Aug 2015
DOI:10.1039/C5GC01411E
A CO2-switchable microemulsion was fabricated by introducing low-cost commercial N,N-dimethyl-N-dodecyl amine into a sodium dodecyl sulphate–butanol–heptane solution. Upon alternate bubbling of CO2 and N2, the system reversibly switched between a monophasic microemulsion and nearly complete phase separation, reflecting the disruption and re-formation of a thermodynamically stable microemulsion.
Co-reporter:Hongyao Yin and Yujun Feng
RSC Advances 2016 vol. 6(Issue 83) pp:79943-79951
Publication Date(Web):17 Aug 2016
DOI:10.1039/C6RA16634B
Polymeric dispersants play a pivotal role in improving graphene solubility in common solvents; however, the presence of such a foreign dispersant may exert a negative influence on the intrinsic properties of graphene. Thus, it is particularly important and challenging to remove the dispersant when graphene is used in end applications. Here, we report a smart graphene dispersion by a CO2-triggered removable diblock polymer – poly(ethylene oxide)-b-poly(N-(3-((3-((4,6-bis((3-(dimethylamino)propyl)amino)-1,3,5-triazin-2-yl)amino)propyl)(methyl)amino)propyl)methacrylamide) (PEA). Using absorption spectroscopy, Raman spectroscopy, XPS spectroscopy and TGA measurements, it was found that PEA can not only strongly interact with graphene to form a stable, concentrated aqueous dispersion, but it can also be removed from the graphene surface upon CO2 treatment as the tertiary amino groups along the polymer chain can be protonated, thus diminishing the affinity for graphene. This study may offer a general strategy for the design of removable dispersants for nanomaterials.
Co-reporter:Hongyao Yin;Anne-Laure Bulteau;Laurent Billon
Advanced Materials Interfaces 2016 Volume 3( Issue 7) pp:
Publication Date(Web):
DOI:10.1002/admi.201500623
Co-reporter:Wei Wang, Hanbin Liu, Meng Mu, Hongyao Yin and Yujun Feng
Polymer Chemistry 2015 vol. 6(Issue 15) pp:2900-2908
Publication Date(Web):13 Feb 2015
DOI:10.1039/C5PY00053J
Well-defined block copolymers represent “stars” among amphiphilic compounds for self-assembly. However, few studies have been directed to their block-random “hybrid” counterparts. In this work, a segmented diblock copolymer containing one random block, PEO113-b-P(4VP90-r-DEAEMA30), was prepared via the RAFT technique from the hydrophilic poly(ethylene oxide) block and a random hydrophobic block copolymerized from 2-(diethylamino)ethyl methacrylate (DEAEMA) and 4-vinyl pyridine (4VP). It was found that first the copolymer in aqueous media could self-assemble into vesicles, which then fuse hierarchically into giant worm-like micelles similar to shish kebab, with length and diameter of ca. 15 μm and 215 nm, respectively. After bubbling CO2 into the copolymer solution up to saturation (pH 5.43), the giant worms transform into polymersomes with a diameter about 75 nm, which is considerably larger than that of the spherical micelles assembled from the same polymer treated with HCl (pH 3.32). The vesicles obtained could revert to worm-like aggregates after depleting CO2 by bubbling N2. Protonation–deprotonation of the PDEAEMA unit, the intensive steric hindrance effect from the adjacent 4VP groups and hydrogen bonding between different 4VP units and free H2O in the interior of polymersomes accounted for such a CO2-driven reversible morphology transition.
Co-reporter:Yongmin Zhang, Yujun Feng
Journal of Colloid and Interface Science 2015 Volume 447() pp:173-181
Publication Date(Web):1 June 2015
DOI:10.1016/j.jcis.2014.11.003
•CO2-induced viscoelastic fluids are formed with sodium erucate and triethylamine.•The fluids viscosity can be switched by CO2.•The fluids irreversibly transform into cloudy dispersion with excess CO2.•The viscosity undergoes five stages of change with continuous bubbling of CO2.Simple “green” triggers such as CO2 for switching viscoelastic surfactant solutions between an “on” and “off” state without compromising their inherent properties have been a key focus of research in smart soft matter over the past decade. Here we report a CO2-induced anionic wormlike micellar fluid by introducing triethylamine (TEA) into natural anionic surfactant sodium erucate (NaOEr) at a molar ratio (CNaOEr:CTEA) of 3:10. When CO2 is bubbled, pH of the solution decreases from 12.3 to 10.0, and TEA is protonated into a quaternary ammonium salt, which facilitates the growth of micelles as a hydrotrope by screening electrostatic repulsion between the anionic headgroups in NaOEr molecules, resulting in the formation of wormlike micelles and viscoelasticity buildup; upon removal of CO2, the quaternized TEA is deprotonated back into a non-ionic tertiary amine, thus electrostatic repulsion strengthens and the viscoelastic fluid converting it back to the initial low viscosity spherical micellar solution. Such a reversible sphere-to-worm transition could be repeated several cycles without any loss of response to CO2 in the pH range of 12.3–10.0, but when further bubbling excess CO2 to pH < 9.50, the solution transforms into a cloudy dispersion with low viscosity due to the de-neutralization of NaOEr, and this process is irreversible. This study offers a facile way to fabricate smart viscoelastic fluids by incorporating a low-molecular weight CO2-sensitive hydrotrope with conventional long-chain surfactants.
Co-reporter:Hanbin Liu, Wei Wang, Hongyao Yin, and Yujun Feng
Langmuir 2015 Volume 31(Issue 32) pp:8756-8763
Publication Date(Web):July 20, 2015
DOI:10.1021/acs.langmuir.5b00885
Polymer worm-like micelles (WLMs) are difficult to target due to the narrow composition window. In this work, we report polymer WLMs self-assembled from a linear ABC triblock copolymer consisting of an intermediate fluorinated block of poly(2,2,3,4,4,4-hexafluorobutyl methacrylate) (F), a hydrophilic segment of poly(ethylene oxide) (O) and a CO2-responsive flank of poly(2-(diethylamino)ethyl methacrylate) (E). In the mixed solvent of water and ethanol, the polymer aggregates evolve from spheres to short rods, then long cylinders and finally WLMs when the volume ratio of water increases from 0 to 50%. Upon the stimulus of CO2, the E block is protonated, thus transforms from hydrophobic to hydrophilic. However, the WLMs just partially return back to spheres even the protonation degree of E block is up to 95%. The closely packed arrangement of fluorinated block caused by the increasing interfacial tension of the fluorinated blocks and solvent could account for the formation of WLMs and its shape alternation under CO2 stimulus.
Co-reporter:Hongyao Yin, Hanbin Liu, Wei Wang, and Yujun Feng
Langmuir 2015 Volume 31(Issue 44) pp:12260-12267
Publication Date(Web):October 20, 2015
DOI:10.1021/acs.langmuir.5b02831
Smart graphene with stimuli-responsive dispersity has great potential for applications in medical and biochemical fields. Nevertheless, reversible dispersion/aggregation of graphene in water with biocompatible and removable trigger still represents a crucial challenge. Here, we report CO2-induced reversible graphene dispersion by noncovalent functionalization of reduced graphene oxide with N2,N4,N6-tris(3-(dimethylamino)propyl)-1,3,5-triazine-2,4,6-triamine (MET). It was demonstrated that MET can be strongly adsorbed on graphene surface through van der Waals interaction to facilitate dispersing graphene in water. Moreover, reversible aggregation/dispersion of graphene can be achieved simply by alternately bubbling CO2 and N2 to control the desorption/adsorption of MET on graphene surface.
Co-reporter:Hanbin Liu, Zanru Guo, Shuai He, Hongyao Yin, Chenhong Fei and Yujun Feng
Polymer Chemistry 2014 vol. 5(Issue 16) pp:4756-4763
Publication Date(Web):10 Apr 2014
DOI:10.1039/C4PY00258J
Precise morphological control over self-assemblies is attractive due to their promising applications, especially in biotherapy. Block copolymer is a common choice for morphological control, since the geometry of self-assemblies can be easily predicted by the hydrophilic volume fraction. However, random copolymers are rarely taken into consideration. Here, starting from the same hydrophilic segment poly(ethylene oxide) (PEO), and using CO2-responsive 2-(diethylamino)ethyl methacrylate (DEAEMA) and hydrophobic styrene (St), we designed and synthesized a random and an entire block copolymer with similar polymerization degrees but different monomer sequences: PEO45-b-(DEAEMA90-r-St66) (Pr) and PEO45-b-DEAEMA93-b-St66 (Pb). In aqueous solution, the two polymers both aggregate into vesicles. Upon CO2-stimulus, however, the vesicle of the random copolymer Pr transforms into a spherical micelle, whereas that of the triblock copolymer Pb shows an expansion instead of a morphological transition. The restricted hydration in the random structure of Pr accounts for such a morphological transition, and the random strategy in polymer design might be useful in self-assembly regulation.
Co-reporter:Hanbin Liu, Ying Zhao, Cécile A. Dreiss and Yujun Feng
Soft Matter 2014 vol. 10(Issue 34) pp:6387-6391
Publication Date(Web):18 Jun 2014
DOI:10.1039/C4SM01207K
CO2-switchable multi-compartment micelles (MCMs) with a segregated corona formed by a purpose-designed ABC triblock copolymer are reported. They can be switched “on” and “off” when sequentially treated with CO2 and N2, due to the protonation–deprotonation of the tertiary amine groups along the polymer skeleton.
Co-reporter:Dingwei Zhu;Yugui Han;Jichao Zhang;Xiaolan Li
Journal of Applied Polymer Science 2014 Volume 131( Issue 19) pp:
Publication Date(Web):
DOI:10.1002/app.40876
ABSTRACT
Organic/inorganic hybrid aqueous solutions were prepared by mixing silica nanoparticle suspension and hydrophobically associating polyacrylamide (HAPAM) solution, and their rheological behaviors were examined in both pure water and brine in comparison with HAPAM. It was found that HAPAM/silica hybrid exhibits viscosity enhancement in aqueous solution and better heat- and salt- tolerances than HAPAM. Meanwhile, their long-term thermal stability is also improved. Cryo-TEM observation reveals that a reinforced three-dimensional network structure of HAPAM/silica hybrid is formed. These improved properties are attributed to the formed hydrogen bond between carbonyl groups in HAPAM skeleton and silanol functionalities in silica nanoparticles in the hybrid system, and the silica nanoparticles in the hybrid act as physical crosslinkers between macromolecules. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40876.
Co-reporter:Hongyao Yin, Yujun Feng, Hanbin Liu, Meng Mu, and Chenhong Fei
Langmuir 2014 Volume 30(Issue 33) pp:9911-9919
Publication Date(Web):2017-2-22
DOI:10.1021/la501461n
Owing to its wide availability, nontoxicity, and low cost, CO2 working as a trigger to reversibly switch material properties, including polarity, ionic strength, hydrophilicity, viscosity, surface charge, and degree of polymerization or cross-linking, has attracted an increasing attention in recent years. However, a quantitative correlation between basicity of these materials and their CO2 switchability has been less documented though it is of great importance for fabricating switchable system. In this work, the “switch-on” and “switch-off” abilities of melamine and its amino-substituted derivatives by introducing and removing CO2 are studied, and then their quantitative relationship with basicity is established, so that performances of other organobases can be quantitatively predicted. These findings are beneficial for forecasting the CO2 stimuli-responsive behavior of other organobases and the design of CO2-switchable materials.
Co-reporter:Yuejiao Wang;Yongmin Zhang;Xingli Liu;Jiyu Wang
Journal of Surfactants and Detergents 2014 Volume 17( Issue 2) pp:295-301
Publication Date(Web):2014 March
DOI:10.1007/s11743-013-1496-7
Ultra-long-chain amidobetaine surfactants have become one of the hot topics recently, but the influence of the hydrophilic head group on the aggregation behaviors and the correlation between surface activities and thickening ability have been less documented. In this work, comparative studies on the effect of the hydrophilic group on Krafft temperature (TK), surface activities and rheological behaviors of erucyl amidobetaines with sulfonate, hydroxyl-sulfonate or carboxylate were examined. Compared to the sulfobetaines, the carboxybetaine is more water-soluble; the addition of an hydroxyl group onto the head group of sulfobetaine increases water-solubility leading to a lower TK. Unexpectedly, the nature of the head groups has little effect on the critical micelle concentration and thickening ability of these surfactants. The packing parameter prediction verifies the formation of wormlike micelles which accounts for the strong thickening ability of the surfactant aqueous solutions.
Co-reporter:Zanru Guo;Dingwei Zhu;Shuai He;Hanbin Liu;Xiangrong Shi;Jing Sun;Meizhen Qu
Advanced Functional Materials 2013 Volume 23( Issue 40) pp:5010-5018
Publication Date(Web):
DOI:10.1002/adfm.201300434
A new type of light-switchable “smart” single-walled carbon nanotube (SWNTs) is developed by the reversible host–guest interaction between azobenzene-terminal PEO (AzoPEO) and pyrene-labeled host attached on the sidewalls of nanotubes via π–π stacking. The SWNTs hybrids not only are well dispersed in pure water, but also exhibit switchable dispersion/aggregation states upon the alternate irradiation of UV and visible light. Moreover, the SWNTs hybrids dispersion is preliminarily used as coating fluid to form transparent conductive films. The dispersant AzoPEO is removed by the contamination-free UV treatment, decreasing the resistance of the films. This kind of light-switchable SWNTs hybrids, possessing a ‘‘green’’ trigger and intact structure of the nanotube, may find potential applications in sensor of biomedicines, device fabrication, etc. Additionally, such a reversible host–guest interaction system may open up the possibility to control the dispersion state of SWNTs by other common polymers.
Co-reporter:Meng Mu, Hongyao Yin, Yujun Feng
Journal of Colloid and Interface Science (1 July 2017) Volume 497() pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.jcis.2017.03.012
HypothesisCO2-responsive microspheres fabricated via co-polymerization protocol are attractive due to their promising applications. However, the inevitable particles-agglomeration restrained their further utilizations. Towards this challenge, interpenetrating network (IPN) protocol would be a potential choice to construct the “intelligent” microspheres, which presents superiority in comparison with co-polymerization mode.ExperimentsA series of CO2-responsive microspheres with polyacrylamide (PAM)/poly(dimethyl aminopropyl methacrylamide) (PDMAPMA) IPN-structure were fabricated via inverse seed suspension polymerization by adjusting DMAPMA loading and crosslinking-degree of seeds. The resultant particles and responsiveness were examined using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), optical microscopy (OM) and laser particle size analyzer (LS), respectively.FindingsThe interior-structure and fracture-morphology of IPN-particles could be intuitively observed by SEM, showing homogeneous and compact structure without phase separation, offering the direct proof for the formation of IPN-microstructures; the particle morphology altered from IPN to IPN-membrane when gradually increasing DMAPMA concentration. Upon alternating treatment with CO2 and N2, these particles experience reversible volume expansion and collapse. Besides, the non-agglomerated responsive particles with varying composition can be prepared by changing the crosslinking-degree of seeds, from which maximum responsiveness, relative swelling volume (RSV), could reach 11.6 when PDMAPMA loading is at 87%.A novel kind of CO2-responsive microspheres with interpenetrating network were developed.
![1-Propanaminium,N,N-dimethyl-N-[3-[(1-oxooctadecyl)amino]propyl]-3-sulfo-, inner salt](http://img.cochemist.com/ccimg/20300/20284-67-7.png)
![1-Propanaminium,N,N-dimethyl-N-[3-[(1-oxooctadecyl)amino]propyl]-3-sulfo-, inner salt](http://img.cochemist.com/ccimg/20300/20284-67-7_b.png)
![N-[3-(dimethylamino)propyl]docos-13-enamide](http://img.cochemist.com/ccimg/150000/149968-48-9.png)
![N-[3-(dimethylamino)propyl]docos-13-enamide](http://img.cochemist.com/ccimg/150000/149968-48-9_b.png)
