{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,11]],"date-time":"2026-07-11T15:04:56Z","timestamp":1783782296742,"version":"3.55.0"},"reference-count":37,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2020,4,25]],"date-time":"2020-04-25T00:00:00Z","timestamp":1587772800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Although equipment-based gas sensor systems (e.g., high-performance liquid chromatography) have been widely applied for formaldehyde gas detection, pre-treatment and expensive instrumentation are required. To overcome these disadvantages, we developed a colorimetric sensor based on polymer-based core\u2013shell nanoparticles (PCSNPs), which are inexpensive, stable, and exhibit enhanced selectivity. Spherical and uniform poly(styrene-co-maleic anhydride) (PSMA)\/polyethyleneimine (PEI) core\u2013shell nanoparticles were prepared and then impregnated with Methyl Red (MR), Bromocresol Purple (BCP), or 4-nitrophenol (4-NP) to construct colorimetric sensors for formaldehyde gas. The intrinsic properties of these dyes were maintained when introduced into the PCSNPs. In the presence of formaldehyde, the MR, BCP, and 4-NP colorimetric sensors changed to yellow, red, and gray, respectively. The colorimetric response was maximized at a PEI\/PSMA ratio of four, likely owing to the high content of amine groups. Effective formaldehyde gas detection was achieved at a relative humidity of 30% using the MR colorimetric sensor, which exhibited a large color change (92%) in 1 min. Advantageously, this stable sensor allowed sensitive and rapid naked-eye detection of low formaldehyde concentrations (0.5 ppm). Hence, this approach is promising for real-time formaldehyde gas visualization and can also be adapted to other colorimetric gas sensor systems to improve sensitivity and simplicity.<\/jats:p>","DOI":"10.3390\/polym12050998","type":"journal-article","created":{"date-parts":[[2020,4,29]],"date-time":"2020-04-29T01:29:15Z","timestamp":1588123755000},"page":"998","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Colorimetric Visualization Using Polymeric Core\u2013Shell Nanoparticles: Enhanced Sensitivity for Formaldehyde Gas Sensors"],"prefix":"10.3390","volume":"12","author":[{"given":"Jae Jung","family":"Park","sequence":"first","affiliation":[{"name":"Department of Chemical and Biomolecular Engineering, Yonsei University Yonsei-ro 50, Seodaemun-gu, Seoul 120-749, Korea"},{"name":"Research Institute of Sustainable Manufacturing System, Intelligent Sustainable Materials R&amp;D Group, Korea Institute of Industrial Technology, 89 Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si, Chungcheongnam-do 31056, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yongsoo","family":"Kim","sequence":"additional","affiliation":[{"name":"Research Institute of Sustainable Manufacturing System, Intelligent Sustainable Materials R&amp;D Group, Korea Institute of Industrial Technology, 89 Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si, Chungcheongnam-do 31056, Korea"},{"name":"Department of Polymer Science &amp; Engineering, Sung Kyun Kwan University 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chanmin","family":"Lee","sequence":"additional","affiliation":[{"name":"Research Institute of Sustainable Manufacturing System, Intelligent Sustainable Materials R&amp;D Group, Korea Institute of Industrial Technology, 89 Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si, Chungcheongnam-do 31056, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jun-Won","family":"Kook","sequence":"additional","affiliation":[{"name":"Research Institute of Sustainable Manufacturing System, Intelligent Sustainable Materials R&amp;D Group, Korea Institute of Industrial Technology, 89 Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si, Chungcheongnam-do 31056, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Donghyun","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Chemical and Biomolecular Engineering, Yonsei University Yonsei-ro 50, Seodaemun-gu, Seoul 120-749, Korea"},{"name":"Research Institute of Sustainable Manufacturing System, Intelligent Sustainable Materials R&amp;D Group, Korea Institute of Industrial Technology, 89 Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si, Chungcheongnam-do 31056, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7965-5103","authenticated-orcid":false,"given":"Jung-Hyun","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Chemical and Biomolecular Engineering, Yonsei University Yonsei-ro 50, Seodaemun-gu, Seoul 120-749, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5554-322X","authenticated-orcid":false,"given":"Ki-Seob","family":"Hwang","sequence":"additional","affiliation":[{"name":"Research Institute of Sustainable Manufacturing System, Intelligent Sustainable Materials R&amp;D Group, Korea Institute of Industrial Technology, 89 Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si, Chungcheongnam-do 31056, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2675-4954","authenticated-orcid":false,"given":"Jun-Young","family":"Lee","sequence":"additional","affiliation":[{"name":"Research Institute of Sustainable Manufacturing System, Intelligent Sustainable Materials R&amp;D Group, Korea Institute of Industrial Technology, 89 Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si, Chungcheongnam-do 31056, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3591","DOI":"10.1021\/ac052111s","article-title":"Colorimetric sensor arrays for volatile organic compounds","volume":"78","author":"Janzen","year":"2006","journal-title":"Anal. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"300","DOI":"10.1016\/j.snb.2013.03.008","article-title":"Detection of formaldehyde vapor using conductive polymer films","volume":"182","author":"BelBruno","year":"2013","journal-title":"Sens. Actuators B Chem."},{"key":"ref_3","unstructured":"Dietrich, K., Yeates, K., Ris, M., Taylor, H., and Pennington, B. (2010). Environmental toxicants. Pediatric Neuropsychology: Research, Theory, and Practice, Guilford Press."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1021\/es00148a016","article-title":"Solubility of gaseous formaldehyde in liquid water and generation of trace standard gaseous formaldehyde","volume":"20","author":"Dong","year":"1986","journal-title":"Environ. Sci. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"821","DOI":"10.1080\/10408440600977669","article-title":"Formaldehyde and glutaraldehyde and nasal cytotoxicity: Case study within the context of the 2006 IPCS Human Framework for the Analysis of a cancer mode of action for humans","volume":"36","author":"McGregor","year":"2006","journal-title":"Crit. Rev. Toxicol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"4046","DOI":"10.1021\/ja910366p","article-title":"A simple and highly sensitive colorimetric detection method for gaseous formaldehyde","volume":"132","author":"Feng","year":"2010","journal-title":"J. Am. Chem. Soc."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1935","DOI":"10.1016\/j.cclet.2017.07.018","article-title":"Recent advances in formaldehyde-responsive fluorescent probes","volume":"28","author":"Xu","year":"2017","journal-title":"Chin. Chem. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"551","DOI":"10.1016\/j.snb.2013.02.043","article-title":"Transportable, fast and high sensitive near real-time analyzers: Formaldehyde detection","volume":"181","author":"Allouch","year":"2013","journal-title":"Sens. Actuators B Chem."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1132","DOI":"10.1016\/j.apr.2017.05.004","article-title":"Indoor air quality during sleep under different ventilation patterns","volume":"8","author":"Canha","year":"2017","journal-title":"Atmos. Pollut. Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1016\/j.jsamd.2016.10.005","article-title":"Highly sensitive and selective chemiresistor gas\/vapor sensors based on polyaniline nanocomposite: A comprehensive review","volume":"1","author":"Pandey","year":"2016","journal-title":"J. Sci. Adv. Mater. Devices"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"17023","DOI":"10.3390\/s121217023","article-title":"Nanostructured metal oxide gas sensors, a survey of applications carried out at SENSOR lab, Brescia (Italy) in the security and food quality fields","volume":"12","author":"Ponzoni","year":"2012","journal-title":"Sensors (Basel)"},{"key":"ref_12","first-page":"1","article-title":"One-dimensional nanostructure based chemiresistor sensor","volume":"10","author":"Pandey","year":"2013","journal-title":"Nanotechnology"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1021\/acssensors.5b00013","article-title":"Au Nanocomposite Based Chemiresistive Ammonia Sensor for Health Monitoring","volume":"1","author":"Pandey","year":"2015","journal-title":"ACS Sens."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1016\/j.aca.2009.08.043","article-title":"An optical reflected device using a molecularly imprinted polymer film sensor","volume":"653","author":"Wu","year":"2009","journal-title":"Anal. Chim. Acta"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/0956-5663(96)88410-7","article-title":"Electrochemical enzyme sensor for formaldehyde operating in the gas phase","volume":"11","author":"Hall","year":"1996","journal-title":"Biosens. Bioelectron."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"273","DOI":"10.5487\/TR.2015.31.3.273","article-title":"Validation and Determination of the Contents of Acetaldehyde and Formaldehyde in Foods","volume":"31","author":"Jeong","year":"2015","journal-title":"Toxicol. Res."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1007\/s12274-018-2207-5","article-title":"Nanomaterials for sensing of formaldehyde in air: Principles, applications, and performance evaluation","volume":"12","author":"Kukkar","year":"2018","journal-title":"Nano Res."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"8121","DOI":"10.1039\/C4CC00914B","article-title":"A colorimetric agarose gel for formaldehyde measurement based on nanotechnology involving Tollens reaction","volume":"50","author":"Zeng","year":"2014","journal-title":"Chem. Commun."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1021\/ac4035168","article-title":"Optical chemical pH sensors","volume":"86","author":"Wencel","year":"2014","journal-title":"Anal. Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2131","DOI":"10.1007\/s00216-006-1061-6","article-title":"Novel coumarin-based fluorescent pH indicators, probes and membranes covering a broad pH range","volume":"387","author":"Vasylevska","year":"2007","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"795","DOI":"10.1002\/adma.201503825","article-title":"Nanostructured Materials for Room-Temperature Gas Sensors","volume":"28","author":"Zhang","year":"2016","journal-title":"Adv. Mater."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1002\/smll.200500261","article-title":"Metal and metal oxide nanoparticles in chemiresistors: Does the nanoscale matter?","volume":"2","author":"Franke","year":"2006","journal-title":"Small"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"9180","DOI":"10.1002\/anie.200903926","article-title":"Synthesis of tin dioxide octahedral nanoparticles with exposed high-energy {221} facets and enhanced gas-sensing properties","volume":"48","author":"Han","year":"2009","journal-title":"Angew. Chem. Int. Ed. Engl."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1083","DOI":"10.1039\/b704562j","article-title":"Gas sensors based on nanostructured materials","volume":"132","author":"Riu","year":"2007","journal-title":"Analyst"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"659","DOI":"10.1016\/j.snb.2006.06.022","article-title":"Chemical sensors based on nanostructured materials","volume":"122","author":"Huang","year":"2007","journal-title":"Sens. Actuators B Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1721","DOI":"10.1021\/ar800035u","article-title":"Gold nanoparticles in biology: Beyond toxicity to cellular imaging","volume":"41","author":"Murphy","year":"2008","journal-title":"Acc. Chem. Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2677","DOI":"10.1007\/s00604-016-1930-4","article-title":"Core-shell nanoparticles coated with molecularly imprinted polymers: A review","volume":"183","author":"Niu","year":"2016","journal-title":"Microchim. Acta"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1597","DOI":"10.1021\/cr400559g","article-title":"Molecular assembly of Schiff Base interactions: Construction and application","volume":"115","author":"Jia","year":"2015","journal-title":"Chem. Rev."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"589","DOI":"10.1177\/0883911507084653","article-title":"Delivery of Doxorubicin from Biodegradable PEG Hydrogels Having Schiff Base Linkages","volume":"22","author":"Saito","year":"2016","journal-title":"J. Bioact. Compat. Polym."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1640","DOI":"10.1016\/j.optmat.2006.08.009","article-title":"Second harmonic generation diagnostic of layer-by-layer deposition from Disperse Red 1\u2013functionalized maleic anhydride copolymer","volume":"29","author":"Aldea","year":"2007","journal-title":"Opt. Mater."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/j.msec.2018.06.015","article-title":"Critical assessment of polymeric nanostructures used as colorimetric ions probes","volume":"92","author":"Stelmach","year":"2018","journal-title":"Mater. Sci. Eng. C"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"645","DOI":"10.1039\/b404098h","article-title":"Fluorescent pH sensors with negligible sensitivity to ionic strength","volume":"129","author":"Weidgans","year":"2004","journal-title":"Analyst"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"907","DOI":"10.1039\/b501306b","article-title":"pH fluorosensors for use in marine systems","volume":"130","author":"Weidgans","year":"2005","journal-title":"Analyst"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1711","DOI":"10.1039\/c0an00180e","article-title":"Red light-excitable dual lifetime referenced optical pH sensors with intrinsic temperature compensation","volume":"135","author":"Borisov","year":"2010","journal-title":"Analyst"},{"key":"ref_35","first-page":"4961","article-title":"Amphiphilic graft copolymer based on poly(styrene-co-maleic anhydride) with low molecular weight polyethylenimine for efficient gene delivery","volume":"7","author":"Duan","year":"2012","journal-title":"Int. J. Nanomed."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"8679","DOI":"10.1021\/acs.analchem.5b01138","article-title":"Diverse states and properties of polymer nanoparticles and gel formed by polyethyleneimine and aldehydes and analytical applications","volume":"87","author":"Ling","year":"2015","journal-title":"Anal. Chem."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"110","DOI":"10.4236\/gsc.2016.62010","article-title":"Application and Mechanism of Malonic Acid as a Green Alternative for Protein-Crosslinking","volume":"6","author":"Szlosek","year":"2016","journal-title":"Green Sustain. Chem."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/12\/5\/998\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:23:45Z","timestamp":1760361825000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/12\/5\/998"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,4,25]]},"references-count":37,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2020,5]]}},"alternative-id":["polym12050998"],"URL":"https:\/\/doi.org\/10.3390\/polym12050998","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,4,25]]}}}