Abstract
Methacrylic acid based microgels have got much consideration in the last two decades because of their potential uses in different fields owing to their responsive behaviour towards external stimuli. Synthesis, properties and uses of methacrylic acid based microgels and their hybrids have been critically reviewed in this article. With minute change in external stimuli such as pH and ionic strength of medium, these microgels show quick swelling/deswelling reversibly. The methacrylic acid based microgels have been widely reported for applications in the area of nanotechnology, drug delivery, sensing and catalysis due to their responsive behaviour. A critical review of current research development in this field along with upcoming perception is presented here. This discussion is concluded with proposed probable future studies for additional growth in this field of research.
About the authors
Iftikhar Hussain is an Assistant Professor of Chemistry at Govt. Dyal Singh Graduate College, Government of the Punjab Higher Education Department. He obtained his PhD degree in Chemistry from University of the Punjab, Lahore under the supervision of Dr. Zahoor H. Farooqi in 2022. He obtained his MPhil Chemistry and MSc Chemistry degree from GCU, Faisalabad and University of the Punjab, Lahore respectively. His area of research is microgels and their hybrids.
Dr. Muhammad Shahid is an Assistant Professor of Chemistry at Government Dyal Singh Graduate College, Government of the Punjab Higher Education Department. He did his PhD in Chemistry under the supervision of Dr. Zahoor H. Farooqi. He obtained his MPhil degree in Chemistry from GCU, Lahore and his MSc degree in Chemistry from UET, Lahore.
Ahmad Irfan graduated from GCES, University of the Punjab (PU) in 2002 and received his MSc (2004) from UAF, Faisalabad. Through a mutual scholarship of MOE, Pakistan and CSC, China he received his PhD (2010) from NENU, China. He worked as Assistant Professor at University of the Punjab, Lahore, Pakistan, and King Khalid University (KKU), Saudi Arabia. He is currently serving as a professor at Department of Chemistry and RCAMS, KKU. His present research interests are advanced functional materials, nanotechnology, catalysis, renewable energy, semiconductors and drug designing.
Zahoor H. Farooqi is an Associate Professor at School of Chemistry, University of the Punjab, Lahore, Pakistan. He worked as research associate in CSI, The City University of New York, USA under Pak-US Science and Technology Cooperative Program (2009–2010). He worked as Honorary Research Fellow in Department of Chemistry, University of Liverpool, UK in 2018. His area of research is polymer colloids and microgels loaded with inorganic nanoparticles for biomedical, environmental and catalytic applications.
Robina Begum is an Assistant Professor at School of Chemistry, University of the Punjab, Lahore. She obtained her PhD degree in Chemistry from the same Institute in 2019. She carried out a part of her research work in the laboratory of Prof. Jianliang Xiao at Department of Chemistry, University of Liverpool, UK, as a Split-Site PhD scholar funded by Commonwealth Scholarship Commission, UK. Her research area is organic-inorganic hybrid materials for various applications.
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Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
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Research funding: Z. H. Farooqi is thankful to Higher Education Commission (HEC), Pakistan (No. 20-3995/NRPU/R&D/HEC/14/1212) and University of the Punjab, Lahore, Pakistan (No. D/72/Est. I) for financial support to carry out this work. A. Irfan is grateful to the King Khalid University, Kingdom of Saudi Arabia for financial support through research grant (R.G.P.1/42/42).
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Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
References
Agrawal, G. and Agrawal, R. (2018). Functional microgels: recent advances in their biomedical applications. Small 14: 1801724.10.1002/smll.201801724Search in Google Scholar PubMed
Ajmal, M., Farooqi, Z.H., and Siddiq, M. (2013). Silver nanoparticles containing hybrid polymer microgels with tunable surface plasmon resonance and catalytic activity. Kor. J. Chem. Eng. 30: 2030–2036.10.1007/s11814-013-0150-4Search in Google Scholar
Ajmal, M., Demirci, S., Siddiq, M., Aktas, N., and Sahiner, N. (2016). Simultaneous catalytic degradation/reduction of multiple organic compounds by modifiable p (methacrylic acid-co-acrylonitrile)–M (M: Cu, Co) microgel catalyst composites. New J. Chem. 40: 1485–1496.10.1039/C5NJ02298CSearch in Google Scholar
Allegretto, J.A., Giussi, J.M., Moya, S.E., Azzaroni, O., and Rafti, M. (2020). Synthesis and characterization of thermoresponsive ZIF-8@PNIPAm-co-MAA microgel composites with enhanced performance as an adsorption/release platform. RSC Adv. 10: 2453–2461.10.1039/C9RA09729ESearch in Google Scholar PubMed PubMed Central
Baroli, B. (2007). Hydrogels for tissue engineering and delivery of tissue-inducing substances. J. Pharm. Sci. 96: 2197–2223.10.1002/jps.20873Search in Google Scholar PubMed
Begum, R., Farooqi, Z.H., and Khan, S.R. (2016). Poly(N-isopropylacrylamide-acrylic acid) copolymer microgels for various applications: a review. Int. J. Polym. Mater. Polym. Biomater. 65: 841–852.10.1080/00914037.2016.1180607Search in Google Scholar
Begum, R., Farooqi, Z.H., Ahmed, E., Naseem, K., Ashraf, S., Sharif, A., and Rehan, R. (2017). Catalytic reduction of 4-nitrophenol using silver nanoparticles-engineered poly(N-isopropylacrylamide-co-acrylamide) hybrid microgels. Appl. Organomet. Chem. 31: e3563.10.1002/aoc.3563Search in Google Scholar
Begum, R., Farooqi, Z.H., Ahmed, E., Sharif, A., Wu, W., and Irfan, A. (2019). Fundamentals and applications of acrylamide based microgels and their hybrids: a review. RSC Adv. 9: 13838–13854.10.1039/C9RA00699KSearch in Google Scholar
Boularas, M., Deniau-Lejeune, E., Alard, V., Tranchant, J.-F., Billon, L., and Save, M. (2016). Dual stimuli-responsive oligo (ethylene glycol)-based microgels: insight into the role of internal structure in volume phase transitions and loading of magnetic nanoparticles to design stable thermoresponsive hybrid microgels. Polym. Chem. 7: 350–363.10.1039/C5PY01078KSearch in Google Scholar
Brugnoni, M., Nickel, A.C., Kröger, L.C., Scotti, A., Pich, A., Leonhard, K., and Richtering, W. (2019). Synthesis and structure of deuterated ultra-low cross-linked poly(N-isopropylacrylamide) microgels. Polym. Chem. 10: 2397–2405.10.1039/C8PY01699BSearch in Google Scholar
Caputo, T.M., Aliberti, A., Cusano, A.M., Ruvo, M., Cutolo, A., and Cusano, A. (2021). Stimuli-responsive hybrid microgels for controlled drug delivery: sorafenib as a model drug. J. Appl. Polym. Sci. 138: 50147–50160.10.1002/app.50147Search in Google Scholar
Chen, Y., Ballard, N., and Bon, S.A. (2013). Waterborne polymer nanogels non-covalently crosslinked by multiple hydrogen bond arrays. Polym. Chem. 4: 387–392.10.1039/C2PY20615CSearch in Google Scholar
Christodoulakis, K. and Vamvakaki, M. (2010a). pH-Responsive microgel particles comprising solely basic or acidic residues, Macromol. Symp. 291: 106–114.10.1002/masy.201050513Search in Google Scholar
Christodoulakis, K.E. and Vamvakaki, M. (2010b). Amphoteric core–shell microgels: contraphilic two-compartment colloidal particles. Langmuir 26: 639–647.10.1021/la902231bSearch in Google Scholar PubMed
Constantin, M., Bucatariu, S., Harabagiu, V., Popescu, I., Ascenzi, P., and Fundueanu, G. (2014). Poly(N-isopropylacrylamide-co-methacrylic acid) pH/thermo-responsive porous hydrogels as self-regulated drug delivery system. Eur. J. Pharm. Sci. 62: 86–95.10.1016/j.ejps.2014.05.005Search in Google Scholar PubMed
Cortez-Lemus, N.A. and Licea-Claverie, A. (2016). Poly(N-vinylcaprolactam), a comprehensive review on a thermoresponsive polymer becoming popular. Prog. Polym. Sci. 53: 1–51.10.1016/j.progpolymsci.2015.08.001Search in Google Scholar
Davaran, S., Alimirzalu, S., Nejati-Koshki, K., Nasrabadi, H.T., Akbarzadeh, A., Khandaghi, A.A., Abbasian, M., and Alimohammadi, S. (2014). Physicochemical characteristics of Fe3O4 magnetic nanocomposites based on poly(N-isopropylacrylamide) for anti-cancer drug delivery. Asian Pac. J. Cancer Prev. 15: 49–54.10.7314/APJCP.2014.15.1.49Search in Google Scholar PubMed
Dragan, E.S. (2014). Design and applications of interpenetrating polymer network hydrogels. A review. Chem. Eng. J. 243: 572–590.10.1016/j.cej.2014.01.065Search in Google Scholar
Echeverria, C., Lopez, D., and Mijangos, C. (2009). UCST responsive microgels of poly(acrylamide−acrylic acid) copolymers: structure and viscoelastic properties. Macromolecules 42: 9118–9123.10.1021/ma901316kSearch in Google Scholar
El-Sherbiny, I.M., Khalil, I.A., and Ali, I.H. (2018). Updates on stimuli-responsive polymers: synthesis approaches and features. In: Polymer gels. Springer, pp. 129–146.10.1007/978-981-10-6086-1_4Search in Google Scholar
Essawy, H.A. (2005). Preparation of macroporous aluminium oxide using template of poly(methacrylic acid-co-glycidylmethacrylate) crosslinked with methylenebisacrylamide. J. Macromol. Sci., Part A: Pure Appl.Chem. 42: 1361–1368.10.1080/10601320500205384Search in Google Scholar
Fallon, M., Halligan, S., Pezzoli, R., Geever, L., and Higginbotham, C.J.G. (2019). Synthesis and characterisation of novel temperature and pH sensitive physically cross-linked poly(N-vinylcaprolactam-co-itaconic acid) hydrogels for drug delivery. Gels 5: 1–13.10.3390/gels5030041Search in Google Scholar PubMed PubMed Central
Farooqi, Z.H., Iqbal, S., Khan, S.R., Kanwal, F., and Begum, R. (2014). Cobalt and nickel nanoparticles fabricated p(NIPAM-co-MAA) microgels for catalytic applications. e-Polym. 14: 313–321.10.1515/epoly-2014-0111Search in Google Scholar
Farooqi, Z.H., Butt, Z., Begum, R., Khan, S.R., Sharif, A., and Ahmed, E. (2015a). Poly (N-isopropylacrylamide-co-methacrylic acid) microgel stabilized copper nanoparticles for catalytic reduction of nitrobenzene. Mater. Sci.-Pol. 33: 627–634.10.1515/msp-2015-0074Search in Google Scholar
Farooqi, Z.H., Naseem, K., Begum, R., and Ijaz, A. (2015b). Catalytic reduction of 2-nitroaniline in aqueous medium using silver nanoparticles functionalized polymer microgels. J. Inorg. Organomet. Polym. Mater. 25: 1554–1568.10.1007/s10904-015-0275-5Search in Google Scholar
Farooqi, Z.H., Begum, R., Naseem, K., Rubab, U., Usman, M., Khan, A., and Ijaz, A. (2016). Fabrication of silver nanoparticles in pH responsive polymer microgel dispersion for catalytic reduction of nitrobenzene in aqueous medium. Russ. J. Phys. Chem. A 90: 2600–2608.10.1134/S0036024416130239Search in Google Scholar
Farooqi, Z.H., Ijaz, A., Begum, R., Naseem, K., Usman, M., Ajmal, M., and Saeed, U. (2018). Synthesis and characterization of inorganic–organic polymer microgels for catalytic reduction of 4-nitroaniline in aqueous medium. Polym. Compos. 39: 645–653.10.1002/pc.23980Search in Google Scholar
Farooqi, Z.H., Khalid, R., Begum, R., Farooq, U., Wu, Q., Wu, W., Ajmal, M., Irfan, A., and Naseem, K. (2019). Facile synthesis of silver nanoparticles in a crosslinked polymeric system by in situ reduction method for catalytic reduction of 4-nitroaniline. Environ. Technol. 40: 2027–2036.10.1080/09593330.2018.1435737Search in Google Scholar PubMed
Fathi, M., Martin, A., and McClements, D.J. (2014). Nanoencapsulation of food ingredients using carbohydrate based delivery systems. Trends Food Sci. Technol. 39: 18–39.10.1016/j.tifs.2014.06.007Search in Google Scholar
Giussi, J.M., Velasco, M.I., Longo, G.S., Acosta, R.H., and Azzaroni, O. (2015). Unusual temperature-induced swelling of ionizable poly(N-isopropylacrylamide)-based microgels: experimental and theoretical insights into its molecular origin. Soft Matter 11: 8879–8886.10.1039/C5SM01853FSearch in Google Scholar PubMed
Giussi, J.M., Moro, M.M., Iborra, A., Cortez, M.L., Di Silvio, D., Conde, I.L., Longo, G.S., Azzaroni, O., and Moya, S. (2020). A study of the complex interaction between poly allylamine hydrochloride and negatively charged poly(N-isopropylacrylamide-co-methacrylic acid) microgels. Soft Matter 16: 881–890.10.1039/C9SM02070ESearch in Google Scholar PubMed
Hamzah, Y.B., Hashim, S., and Abd Rahman, W.A.W. (2017). Synthesis of polymeric nano/microgels: a review. J. Polym. Res. 24: 1–19.10.1007/s10965-017-1281-9Search in Google Scholar
Hoare, T. and Pelton, R. (2008). Characterizing charge and crosslinker distributions in polyelectrolyte microgels. Curr. Opin. Colloid Interface Sci. 13: 413–428.10.1016/j.cocis.2008.03.004Search in Google Scholar
Hou, W., Shen, Y., Liu, H., Zhang, A., and Dai, S. (2014). Mechanical properties of pH-responsive poly(2-hydroxyethyl methacrylate/methacrylic acid) microgels prepared by inverse microemulsion polymerization. React. Funct. Polym. 74: 101–106.10.1016/j.reactfunctpolym.2013.11.003Search in Google Scholar
Hussain, I., Farooqi, Z.H., Ali, F., Begum, R., Irfan, A., Wu, W., Wang, X., Shahid, M., and Nisar, J. (2021). Poly (styrene@ N-isopropylmethacrylamide-co-methacrylic acid)@ Ag hybrid particles with excellent catalytic potential. J. Mol. Liq. 335: 116106.10.1016/j.molliq.2021.116106Search in Google Scholar
Iqbal, S., Zahoor, C., Musaddiq, S., Hussain, M., Begum, R., Irfan, A., Azam, M., and Farooqi, Z.H. (2020). Silver nanoparticles stabilized in polymer hydrogels for catalytic degradation of azo dyes. Ecotoxicol. Environ. Saf. 202: 110924.10.1016/j.ecoenv.2020.110924Search in Google Scholar PubMed
Islam, M., Tan, J., Kwok, C., and Tam, K. (2019). Drug release kinetics of pH-responsive microgels of different glass-transition temperatures. J. Appl. Polym. Sci. 136: 47284.10.1002/app.47284Search in Google Scholar
Kamal, H. (2014). Removal of methylene blue from aqueous solutions using composite hydrogel prepared by gamma irradiation. J. Am. Sci. 10: 125–133.Search in Google Scholar
Kanamala, M., Wilson, W.R., Yang, M., Palmer, B.D., and Wu, Z. (2016). Mechanisms and biomaterials in pH-responsive tumour targeted drug delivery: a review. Biomaterials 85: 152–167.10.1016/j.biomaterials.2016.01.061Search in Google Scholar PubMed
Kang, M. and Kim, J.C. (2010). FITC-dextran releases from chitosan microgel coated with poly(N-isopropylacrylamide-co-methacrylic acid). Polym. Test. 29: 784–792.10.1016/j.polymertesting.2010.07.002Search in Google Scholar
Karg, M. (2012). Multifunctional inorganic/organic hybrid microgels. Colloid Polym. Sci. 290: 673–688.10.1007/s00396-012-2644-8Search in Google Scholar
Kawaguchi, H., Fujimoto, K., Saito, M., Kawasaki, T., and Urakami, Y. (1993). Preparation and modification of monodisperse hydrogel microspheres. Polym. Int. 30: 225–231.10.1002/pi.4990300215Search in Google Scholar
Khan, M.S., Khan, G.T., Khan, A., and Sultana, S. (2013a). Preparation and characterization of novel temperature and pH sensitive (NIPAM-co-MAA) polymer microgels and their volume phase change with various salts. Polymer 37: 794–801.10.7317/pk.2013.37.6.794Search in Google Scholar
Khan, S.R., Farooqi, Z.H., Ajmal, M., Siddiq, M., and Khan, A. (2013b). Synthesis, characterization, and silver nanoparticles fabrication in N-isopropylacrylamide-based polymer microgels for rapid degradation of p-nitrophenol. J. Dispersion Sci. Technol. 34: 1324–1333.10.1080/01932691.2012.744690Search in Google Scholar
Khan, S.R., Jamil, S., Li, S., and Sultan, A. (2018). Acrylic acid and methacrylic acid based microgel catalysts for reduction of 4-nitrophenol. Russ. J. Phys. Chem. A 92: 2656–2664.10.1134/S003602441901014XSearch in Google Scholar
Kleinen, J., Richtering, W. (2011). Polyelectrolyte microgels based on poly-N-isopropylacrylamide: influence of charge density on microgel properties, binding of poly-diallyldimethylammonium chloride, and properties of polyelectrolyte complexes. Colloid Polym. Sci. 289: 739–749.10.1007/s00396-011-2401-4Search in Google Scholar
Klinger, D. and Landfester, K. (2011). Dual stimuli-responsive poly(2-hydroxyethyl methacrylate-co-methacrylic acid) microgels based on photo-cleavable cross-linkers: pH-dependent swelling and light-induced degradation. Macromolecules 44: 9758–9772.10.1021/ma201706rSearch in Google Scholar
Kobayashi, C., Watanabe, T., Murata, K., Kureha, T., and Suzuki, D. (2016). Localization of polystyrene particles on the surface of poly(N-isopropylacrylamide-co-methacrylic acid) microgels prepared by seeded emulsion polymerization of styrene. Langmuir 32: 1429–1439.10.1021/acs.langmuir.5b03698Search in Google Scholar PubMed
Kubilay, S., Demirci, S., Can, M., Aktas, N., and Sahiner, N. (2021). Dichromate and arsenate anion removal by PEI microgel, cryogel, and bulkgel. J. Environ. Chem. Eng. 9: 104799.10.1016/j.jece.2020.104799Search in Google Scholar
Kwok, M.-h. and Ngai, T. (2018). Emulsions stabilized by pH-responsive PNIPAM-based microgels: effect of spatial distribution of functional carboxylic groups on the emulsion stability. J. Taiwan Inst. Chem. Eng. 92: 97–105.10.1016/j.jtice.2018.01.041Search in Google Scholar
Li, S. (2010). Removal of crystal violet from aqueous solution by sorption into semi-interpenetrated networks hydrogels constituted of poly(acrylic acid-acrylamide-methacrylate) and amylose. Bioresour. Technol. 101: 2197–2202.10.1016/j.biortech.2009.11.044Search in Google Scholar PubMed
Liu, J., Shu, T., Su, L., Zhang, X., and Serpe, M.J. (2018). Synthesis of poly(N-isopropylacrylamide)-co-(acrylic acid) microgel-entrapped CdS quantum dots and their photocatalytic degradation of an organic dye. RSC Adv 8: 16850–16857.10.1039/C8RA01855CSearch in Google Scholar
Liu, L., Zeng, J., Zhao, X., Tian, K., and Liu, P. (2017). Independent temperature and pH dual-responsive PMAA/PNIPAM microgels as drug delivery system: effect of swelling behaviour of the core and shell materials in fabrication process. Colloids Surf., A 526: 48–55.10.1016/j.colsurfa.2016.11.007Search in Google Scholar
Liu, R., Milani, A.H., Freemont, T.J., and Saunders, B.R. (2011). Doubly crosslinked pH-responsive microgels prepared by particle inter-penetration: swelling and mechanical properties. Soft Matter 7: 4696–4704.10.1039/c1sm05216kSearch in Google Scholar
Liu, Y.Y., Liu, X.Y., Yang, J.M., Lin, D.L., Chen, X., and Zha, L.S. (2012). Investigation of Ag nanoparticles loading temperature responsive hybrid microgels and their temperature controlled catalytic activity. Colloids Surf. A Physicochem. Eng. 393: 105–110.10.1016/j.colsurfa.2011.11.007Search in Google Scholar
Lorbeer, L., Alaghemandi, M., and Spohr, E. (2014). Molecular dynamics studies of poly(N-isopropylacrylamide) endgrafted on the surfaces of model slab pores. J. Mol. Liq. 189: 57–62.10.1016/j.molliq.2013.05.022Search in Google Scholar
Lu, D., Zhu, M., Wu, S., Wang, W., Lian, Q., and Saunders, B.R. (2019). Triply responsive coumarin-based microgels with remarkably large photo-switchable swelling. Polym. Chem. 10: 2516–2526.10.1039/C9PY00233BSearch in Google Scholar
Mahkam, M. (2005). Using pH-sensitive hydrogels containing cubane as a crosslinking agent for oral delivery of insulin. J. Biomed. Mater. Res., Part B 75: 108–112.10.1002/jbm.b.30279Search in Google Scholar PubMed
Marcelo, G., Areias, L.R., Viciosa, M.T., Martinho, J., and Farinha, J.P.S. (2017). PNIPAm-based microgels with a UCST response. Polymer 116: 261–267.10.1016/j.polymer.2017.03.071Search in Google Scholar
Marcelo, G., Areias, L.R., Macoas, E., Mendicuti, F., Valiente, M., Martinho, J., and Farinha, J.P.S. (2019). Structural color and rheology of self-assembled poly(N-isopropylacrylamide-methacrylic acid) microgels in water. Eur. Polym. J. 113: 349–356.10.1016/j.eurpolymj.2019.01.070Search in Google Scholar
Marinsky, J.A. (1985). An interpretation of the sensitivity of weakly acidic (basic) polyelectrolyte (cross-linked and linear) equilibria to excess neutral salt. J. Phys. Chem. 89: 5294–5302.10.1021/j100270a035Search in Google Scholar
Mo, J., Yang, Q., Zhang, N., Zhang, W., Zheng, Y., and Zhang, Z. (2018). A review on agro-industrial waste (AIW) derived adsorbents for water and wastewater treatment. J. Environ. Manag. 227: 395–405.10.1016/j.jenvman.2018.08.069Search in Google Scholar PubMed
Mohapatra, H., Kruger, T.M., Lansakara, T.I., Tivanski, A.V., and Stevens, L.L. (2017). Core and surface microgel mechanics are differentially sensitive to alternative crosslinking concentrations. Soft Matter 13: 5684–5695.10.1039/C7SM00727BSearch in Google Scholar PubMed PubMed Central
Naseem, K., Begum, R., and Farooqi, Z.H. (2017). Catalytic reduction of 2-nitroaniline: a review. Environ. Sci. Pollut. Res. 24: 6446–6460.10.1007/s11356-016-8317-2Search in Google Scholar PubMed
Naseem, K., Begum, R., Wu, W., Irfan, A., and Farooqi, Z.H. (2018a). Advancement in multi-functional poly (styrene)-poly (N-isopropylacrylamide) based core–shell microgels and their applications. Polym. Rev. 58: 288–325.10.1080/15583724.2017.1423326Search in Google Scholar
Naseem, K., Ur Rehman, M.A., and Huma, R. (2018b). Review on vinyl acetic acid-based polymer microgels for biomedical and other applications. Int. J. Polym. Mater. 67: 322–332.10.1080/00914037.2017.1327434Search in Google Scholar
Naseem, K., Begum, R., Wu, W., Irfan, A., Al-Sehemi, A.G., and Farooqi, Z.H. (2019). Catalytic reduction of toxic dyes in the presence of silver nanoparticles impregnated core-shell composite microgels. J. Cleaner Prod. 211: 855–864.10.1016/j.jclepro.2018.11.164Search in Google Scholar
Olea, A. and Thomas, J. (1989). Fluorescence studies of the conformational changes of poly (methacrylic acid) with pH. Macromolecules 22: 1165–1169.10.1021/ma00193a029Search in Google Scholar
Panic, V.V., Madzarevic, Z.P., Volkov-Husovic, T., and Velickovic, S.J. (2013). Poly(methacrylic acid) based hydrogels as sorbents for removal of cationic dye basic yellow 28: kinetics, equilibrium study and image analysis. Chem. Eng. J. 217: 192–204.10.1016/j.cej.2012.11.081Search in Google Scholar
Park, K. (2014). Controlled drug delivery systems: past forward and future back. J. Control. Release 190: 3–8.10.1016/j.jconrel.2014.03.054Search in Google Scholar PubMed PubMed Central
Pérez-Juste, J., Pastoriza-Santos, I. and Liz-Marzán, L.M.J. (2013). Multifunctionality in metal@ microgel colloidal nanocomposites.J. Mater. Chem. A 1: 20–26.10.1039/C2TA00112HSearch in Google Scholar
Plamper, F.A. and Richtering, W. (2017). Functional microgels and microgel systems. Acc. Chem. Res. 50: 131–140.10.1021/acs.accounts.6b00544Search in Google Scholar PubMed
Ratemi, E. (2018). pH-responsive polymers for drug delivery applications. Stimuli responsive polymeric nanocarriers for drug delivery applications. 1: 121–141.10.1016/B978-0-08-101997-9.00005-9Search in Google Scholar
Sabadasch, V., Wiehemeier, L., Kottke, T., and Hellweg, T. (2020). Core–shell microgels as thermoresponsive carriers for catalytic palladium nanoparticles. Soft Matter 16: 5422–5430.10.1039/D0SM00433BSearch in Google Scholar
Sanzari, I., Buratti, E., Huang, R., Tusan, C.G., Dinelli, F., Evans, N.D., Prodromakis, T., and Bertoldo, M. (2020). Poly(N-isopropylacrylamide) based thin microgel films for use in cell culture applications. Sci. Rep. 10: 1–14.10.1038/s41598-020-63228-9Search in Google Scholar PubMed PubMed Central
Saunders, B.R. and Vincent, B. (1999). Microgel particles as model colloids: theory, properties and applications. Adv. Colloid Interface Sci. 80: 1–25.10.1016/S0001-8686(98)00071-2Search in Google Scholar
Saunders, B.R., Crowther, H.M., and Vincent, B. (1997). Poly[(methyl methacrylate)-co-(methacrylic acid)] microgel particles: swelling control using pH, cononsolvency, and osmotic deswelling. Macromolecules 30: 482–487.10.1021/ma961277fSearch in Google Scholar
Saunders, B.R., Laajam, N., Daly, E., Teow, S., Hu, X., and Stepto, R. (2009). Microgels: from responsive polymer colloids to biomaterials. Adv. Colloid Interface Sci. 147: 251–262.10.1016/j.cis.2008.08.008Search in Google Scholar PubMed
Schmidt, S., Liu, T., Rütten, S., Phan, K.H., Möller, M., and Richtering, W. (2011). Influence of microgel architecture and oil polarity on stabilization of emulsions by stimuli-sensitive core–shell poly(N-isopropylacrylamide-co-methacrylic acid) microgels: mickering versus pickering behaviour? Langmuir 27: 9801–9806.10.1021/la201823bSearch in Google Scholar PubMed
Shahid, M., Farooqi, Z.H., Begum, R., Naseem, K., Ajmal, M., and Irfan, A. (2018). Designed synthesis of silver nanoparticles in responsive polymeric system for their thermally tailored catalytic activity towards hydrogenation reaction. Kor. J. Chem. Eng. 35: 1099–1107.10.1007/s11814-018-0016-xSearch in Google Scholar
Shahid, M., Farooqi, Z.H., Begum, R., Arif, M., Irfan, A., and Azam, M. (2020a). Extraction of cobalt ions from aqueous solution by microgels for in-situ fabrication of cobalt nanoparticles to degrade toxic dyes: a two fold-environmental application. Chem. Phys. Lett. 754: 137645.10.1016/j.cplett.2020.137645Search in Google Scholar
Shahid, M., Farooqi, Z.H., Begum, R., Arif, M., Wu, W., and Irfan, A. (2020b). Hybrid microgels for catalytic and photocatalytic removal of nitroarenes and organic dyes from aqueous medium: a review. Crit. Rev. Anal. Chem. 50: 513–537.10.1080/10408347.2019.1663148Search in Google Scholar PubMed
Sheikholeslami, P., Ewaschuk, C.M., Ahmed, S.U., Greenlay, B.A., and Hoare, T. (2012). Semi-batch control over functional group distributions in thermoresponsive microgels. Colloid Polym. Sci. 290: 1181–1192.10.1007/s00396-012-2642-xSearch in Google Scholar
Shi, S., Wang, Q., Wang, T., Ren, S., Gao, Y., and Wang, N. (2014). Thermo-, pH-, and light-responsive poly (N-isopropylacrylamide-co-methacrylic acid)–Au hybrid microgels prepared by the in situ reduction method based on au-thiol chemistry. J. Phys. Chem B. 118: 7177–7186.10.1021/jp5027477Search in Google Scholar PubMed
Singh, S.K., Dhyani, A., and Juyal, D. (2017). Hydrogel: preparation, characterization and applications. J. Pharm. Innov. 6: 25–32.Search in Google Scholar
Su, W., Zhao, K., Wei, J., and Ngai, T. (2014). Dielectric relaxations of poly(N-isopropylacrylamide) microgels near the volume phase transition temperature: impact of cross-linking density distribution on the volume phase transition. Soft Matter 10: 8711–8723.10.1039/C4SM01516ASearch in Google Scholar PubMed
Sun, X.F., Feng, Y., Shi, X., and Wang, Y. (2016). Preparation and property of xylan/poly(methacrylic acid) semi-interpenetrating network hydrogel. Int. J. Polym. Sci. 1–8.10.1155/2016/8241078Search in Google Scholar
Tan, J.P. and Tam, K.C. (2007). Application of drug selective electrode in the drug release study of pH-responsive microgels. J. Control. Release 118: 87–94.10.1016/j.jconrel.2006.11.017Search in Google Scholar PubMed
Torres-Lugo, M. and Peppas, N.A. (1999). Molecular design and in vitro studies of novel pH-sensitive hydrogels for the oral delivery of calcitonin. Macromolecules 32: 6646–6651.10.1021/ma990541cSearch in Google Scholar
Tu, H., Qu, Y., Hu, X., Yin, Y., Zheng, H., Xu, P., and Xiong, F. (2010). Study of the sigmoidal swelling kinetics of carboxymethylchitosan-g-poly (acrylic acid) hydrogels intended for colon-specific drug delivery. Carbohydr. Polym. 82: 440–445.10.1016/j.carbpol.2010.04.086Search in Google Scholar
Wang, J., Huang, N., Peng, Q., Cheng, X., and Li, W. (2020a). Temperature/pH dual-responsive and luminescent drug carrier based on PNIPAM-MAA/lanthanide-polyoxometalates for controlled drug delivery and imaging in HeLa cells. Mater. Chem. Phys. 239: 121994.10.1016/j.matchemphys.2019.121994Search in Google Scholar
Wang, J., Liu, Y., Li, X., Luo, Y., Zheng, L., Hu, J., Chen, G., and Chen, H. (2020b). Ultralow crosslinked microgel brings ultrahigh catalytic efficiency. Macromol. Rapid Commun. 41: 2000135.10.1002/marc.202000135Search in Google Scholar PubMed
Watanabe, T., Kobayashi, C., Song, C., Murata, K., Kureha, T., and Suzuki, D. (2016). Impact of spatial distribution of charged groups in core poly(N-isopropylacrylamide)-based microgels on the resultant composite structures prepared by seeded emulsion polymerization of styrene. Langmuir 32: 12760–12773.10.1021/acs.langmuir.6b03172Search in Google Scholar PubMed
Wong, J.E., Díez-Pascual, A.M., and Richtering, W. (2009). Layer-by-Layer assembly of polyelectrolyte multilayers on thermoresponsive P(NiPAM-co-MAA) microgel: effect of ionic strength and molecular weight. Macromolecules 42: 1229–1238.10.1021/ma802072cSearch in Google Scholar
Xiao, C., Wu, Q., Chang, A., Peng, Y., Xu, W., and Wu, W. (2014). Responsive Au@ polymer hybrid microgels for the simultaneous modulation and monitoring of Au-catalyzed chemical reaction. J. Mater. Chem. A. 2: 9514–9523.10.1039/c4ta00409dSearch in Google Scholar
Yang, D., Eronen, H., Tenhu, H., and Hietala, S. (2021). Phase transition behaviour and catalytic activity of poly(N-acryloylglycinamide-co-methacrylic acid) microgels. Langmuir 37: 2639–2648.10.1021/acs.langmuir.0c03264Search in Google Scholar PubMed PubMed Central
Yang, L.Q., Hao, M.M., Wang, H.Y., and Zhang, Y. (2015). Amphiphilic polymer-Ag composite microgels with tunable catalytic activity and selectivity. Colloid Polym. Sci. 293: 2405–2417.10.1007/s00396-015-3642-4Search in Google Scholar
Yoshida, R. and Okano, T. (2010). Stimuli-responsive hydrogels and their application to functional materials. In: Biomedical applications of hydrogels handbook. Springer, pp. 19–43.10.1007/978-1-4419-5919-5_2Search in Google Scholar
Zhai, Z., Wu, Q., Li, J., Zhou, B., Shen, J., Farooqi, Z.H., and Wu, W. (2019). Enhanced catalysis of gold nanoparticles in microgels upon on site altering the gold–polymer interface interaction. J. Catal. 369: 462–468.10.1016/j.jcat.2018.10.037Search in Google Scholar
Zhang, Q.M. and Serpe, M.J. (2015). Versatile method for coating surfaces with functional and responsive polymer-based films. ACS Appl. Mater. Interfaces 7: 27547–27553.10.1021/acsami.5b09875Search in Google Scholar PubMed
Zhang, Y., Fang, Y., Wang, S. and Lin, S. (2004). Preparation of spherical nanostructured poly (methacrylic acid)/PbS composites by a microgel template method. J. Colloid Interface Sci. 272: 321–325.10.1016/j.jcis.2004.01.053Search in Google Scholar PubMed
Zhang, Y., Liu, H., and Fang, Y. (2011). Preparation of CuS-P(NIPAM-co-MAA) hybrid microgels with controlled surface structures. Chin. J. Chem. 29: 33–40.10.1002/cjoc.201190057Search in Google Scholar
Zhang, Y., Gu, W., Zhao, J., and Qin, Z. (2017). A facile, efficient and “green” route to pH-responsive crosslinked poly (methacrylic acid) nanoparticles. Colloids Surf., A 531: 1–8.10.1016/j.colsurfa.2017.07.062Search in Google Scholar
Zhao, G., Wu, X., Tan, X., and Wang, X. (2010). Sorption of heavy metal ions from aqueous solutions: a review. Open Colloid Sci. J. 4: 19–31.10.2174/1876530001104010019Search in Google Scholar
Zhou, S. and Chu, B. (1998). Synthesis and volume phase transition of poly (methacrylic acid-co-N-isopropylacrylamide) microgel particles in water. J. Phys. Chem. B 102: 1364–1371.10.1021/jp972990pSearch in Google Scholar
Zhu, H., Li, Y., Qiu, R., Shi, L., Wu, W., and Zhou, S. (2012). Responsive fluorescent Bi2O3@ PVA hybrid nanogels for temperature-sensing, dual-modal imaging, and drug delivery. Biomaterials 33: 3058–3069.10.1016/j.biomaterials.2012.01.003Search in Google Scholar PubMed
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