{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T09:23:20Z","timestamp":1787304200434,"version":"build-2736575974"},"reference-count":60,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T00:00:00Z","timestamp":1787270400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001843","name":"SERB DST","doi-asserted-by":"publisher","award":["CRG\/2023\/000268"],"award-info":[{"award-number":["CRG\/2023\/000268"]}],"id":[{"id":"10.13039\/501100001843","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Poly(vinyl alcohol) (PVA)\u2013bentonite composite coatings combine a hydrophilic polymer with a naturally abundant clay mineral, offering potential advantages for modifying the physicochemical and film-forming characteristics of polymer\u2013clay coatings. However, the combined influence of PVA\u2013bentonite composition and total solids content on drying behavior and film evolution remains insufficiently explored. This study investigates the particle size, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), surface morphology, rheology, thixotropy, zeta potential, drying behavior, solvent transport, and film evolution of PVA\u2013bentonite coatings prepared at total solids contents of 5 and 10 wt.% with different PVA to bentonite ratios. The drying profiles exhibited an initial relatively rapid solvent-removal stage followed by a slower stage associated with progressively restricted solvent transport during film consolidation. A lower total solids content (5 wt.%) generally accelerated drying but was associated with greater microcracking, whereas a higher total solids content (10 wt.%) produced more consolidated and comparatively uniform films with reduced solvent mobility. The combined physicochemical, rheological, drying, and morphological results demonstrate that both PVA\u2013bentonite composition and total solids content substantially influence the structural organization and drying behavior of the coatings. Pure PVA formed a relatively uniform film but exhibited prolonged drying, while pure bentonite required the longest drying time (1083 min). Among the investigated formulations, the 50:50 PVA\u2013bentonite coating demonstrated the shortest drying time, reaching equilibrium in approximately 480 min, while also exhibiting comparatively good film uniformity. During drying, its thickness decreased from approximately 1745 to 440 \u00b5m, corresponding to a reduction of about 1305 \u00b5m. Overall, under the investigated laboratory conditions, the 50:50 PVA\u2013bentonite formulation provided the most favorable balance of drying behavior, film formation, and rheological characteristics among the compositions studied. These findings provide composition\u2013structure\u2013drying relationships that can guide further development of PVA\u2013bentonite coating systems. At the same time, additional evaluation of mechanical, adhesion, barrier, durability, and economic performance is required to establish broader practical applicability.<\/jats:p>","DOI":"10.3390\/polym18162025","type":"journal-article","created":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T08:14:01Z","timestamp":1787300041000},"page":"2025","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Mechanistic Insights into Drying and Film Evolution of PVA\u2013Bentonite Coatings: The Role of Solids Content and Coating Composition Optimization"],"prefix":"10.3390","volume":"18","author":[{"given":"Sarojini","family":"Verma","sequence":"first","affiliation":[{"name":"Department of Chemical Engineering, Dr. B.R. Ambedkar National Institute of Technology, Jalandhar 144011, Punjab, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9013-3311","authenticated-orcid":false,"given":"George D.","family":"Verros","sequence":"additional","affiliation":[{"name":"Laboratory of Polymer and Dyes Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki (Auth), 54124 Thessaloniki, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1210-108X","authenticated-orcid":false,"given":"Raj Kumar","family":"Arya","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Dr. B.R. Ambedkar National Institute of Technology, Jalandhar 144011, Punjab, India"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"791","DOI":"10.1002\/aic.690440404","article-title":"Drying kinetics of polymer films","volume":"44","author":"Guerrier","year":"1998","journal-title":"AIChE J."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Bryntesen, S.N., Kahrom, A., Lamb, J.J., Tolstorebrov, I., and Burheim, O.S. (2023). Experimental Analysis of Drying Kinetics and Quality Aspects of Convection-Dried Cathodes at Laboratory Scale. Batteries, 9.","DOI":"10.3390\/batteries9020096"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"41737","DOI":"10.1002\/app.41737","article-title":"Hydrophobically modified poly(vinyl alcohol) and bentonite nanocomposites thereof: Barrier, mechanical, and aesthetic properties","volume":"132","author":"Johansson","year":"2015","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1812","DOI":"10.1002\/app.34651","article-title":"Properties of poly(vinyl alcohol)\u2014Bentonite clay nanocomposite films in relation to polymer\u2013clay interactions","volume":"123","author":"Sapalidis","year":"2012","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Verma, S., Verros, G.D., and Arya, R.K. (2025). PVA-Bentonite-Water Coatings: Experimental and Simulation Studies. Polymers, 17.","DOI":"10.3390\/polym17192689"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"10506","DOI":"10.1021\/acs.iecr.7b02334","article-title":"Fundamental Investigation of the Drying of Solid Suspensions","volume":"56","author":"Osman","year":"2017","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1231","DOI":"10.1016\/j.jcis.2020.08.055","article-title":"Using an added liquid to suppress drying defects in hard particle coatings","volume":"582","author":"Fischer","year":"2021","journal-title":"J. Colloid Interface Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"107500","DOI":"10.1016\/j.clay.2024.107500","article-title":"Investigating the drying behaviour of clay-containing slurries","volume":"260","author":"Kashif","year":"2024","journal-title":"Appl. Clay Sci."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Nechita, P. (2021). The Influence of Drying Conditions of Clay-Based Polymer Coatings on Coated Paper Properties. Coatings, 11.","DOI":"10.3390\/coatings11010012"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1016\/j.crci.2018.11.011","article-title":"Hectorite and bentonite effect on water-based polymer coating rheology","volume":"22","author":"Birks","year":"2019","journal-title":"Comptes Rendus Chim."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Amari, A., Mohammed Alzahrani, F., Mohammedsaleh Katubi, K., Salem Alsaiari, N., Tahoon, M.A., and Ben Rebah, F. (2021). Clay-Polymer Nanocomposites: Preparations and Utilization for Pollutants Removal. Materials, 14.","DOI":"10.3390\/ma14061365"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2061","DOI":"10.1080\/07373939708917352","article-title":"Drying of a paper coating: Experimental study and modelling","volume":"15","author":"Bemada","year":"1997","journal-title":"Dry. Technol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"108618","DOI":"10.1016\/j.porgcoat.2024.108618","article-title":"Impact of resin molecular weight on drying kinetics and sag of coatings","volume":"194","author":"Issa","year":"2024","journal-title":"Prog. Org. Coat."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"10326","DOI":"10.1039\/D0SM01504K","article-title":"Stratification of polymer\u2013colloid mixtures via fast nonequilibrium evaporation","volume":"16","author":"Lee","year":"2020","journal-title":"Soft Matter"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1002\/aic.690480105","article-title":"Drying process paths of ternary polymer solution coating","volume":"48","author":"Dabral","year":"2002","journal-title":"AIChE J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"688","DOI":"10.1002\/jbm.b.31336","article-title":"Modeling solvent evaporation during the manufacture of controlled drug-release coatings and the impact on release kinetics","volume":"90B","author":"Kim","year":"2009","journal-title":"J. Biomed. Mater. Res. Part B Appl. Biomater."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"S4119","DOI":"10.1088\/0953-8984\/17\/49\/008","article-title":"Solvent evaporation and interdiffusion in polymer films","volume":"17","author":"Tsige","year":"2005","journal-title":"J. Phys. Condens. Matter"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Cussler, E.L. (2009). Diffusion: Mass Transfer in Fluid Systems, Cambridge University Press.","DOI":"10.1017\/CBO9780511805134"},{"key":"ref_19","unstructured":"Crank, J. (1975). The Mathematics of Diffusion, Oxford University Press."},{"key":"ref_20","first-page":"203","article-title":"The drying of porous solids: Diffusion calculations","volume":"27","author":"Newman","year":"1931","journal-title":"Trans. Am. Inst. Chem. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Mujumdar, A.S. (2006). Handbook of Industrial Drying, CRC Press.","DOI":"10.1201\/9781420017618"},{"key":"ref_22","unstructured":"Crank, J., and Park, G. (1968). Diffusion in Polymers, Academic Press."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"58006","DOI":"10.1021\/acsami.4c09729","article-title":"From wet to protective: Film formation in waterborne coatings","volume":"16","author":"Arjmandi","year":"2024","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1279","DOI":"10.1002\/app.1995.070580809","article-title":"Modeling and design of an industrial dryer with convective and radiant heating","volume":"58","author":"Cairncross","year":"1995","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1991","DOI":"10.1081\/DRT-120026429","article-title":"Three-Layer Model for Drying of Coating Applied on Silicone-Coated Paper","volume":"21","author":"Jain","year":"2003","journal-title":"Dry. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1016\/0014-3057(95)00146-8","article-title":"Application of Flory-Huggins theory to ternary polymer-solvents equilibria: A case study","volume":"32","author":"Favre","year":"1996","journal-title":"Eur. Polym. J."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1508","DOI":"10.1039\/D4SM01215A","article-title":"Diffusive evaporation dynamics in polymer solutions is ubiquitous","volume":"21","author":"Huisman","year":"2025","journal-title":"Soft Matter"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Shalygina, T.A., Rudenko, M.S., Nemtsev, I.V., Parfenov, V.A., Voronina, S.Y., Simonov-Emelyanov, I.D., and Borisova, P.E. (2021). Influence of the Filler Particles\u2019 Surface Morphology on the Polyurethane Matrix\u2019s Structure Formation in the Composite. Polymers, 13.","DOI":"10.3390\/polym13223864"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1016\/j.porgcoat.2017.10.002","article-title":"Effect of crosslinked polymer content on drying of binary polymer\u2014Solvent coatings","volume":"114","author":"Pathania","year":"2018","journal-title":"Prog. Org. Coat."},{"key":"ref_30","unstructured":"Barnes, H.A., Hutton, J.F., and Walters, K. (1989). An Introduction to Rheology, Elsevier."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Mezger, T. (2020). The Rheology Handbook: For Users of Rotational and Oscillatory Rheometers, European Coatings.","DOI":"10.1515\/9783748603702"},{"key":"ref_32","unstructured":"Macosko, C.W. (1994). Rheology: Principles, Measurements, and Applications, Wiley-VCH, Inc.. [1st ed.]."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1539","DOI":"10.1016\/j.progpolymsci.2003.08.002","article-title":"Polymer\/layered silicate nanocomposites: A review from preparation to processing","volume":"28","author":"Ray","year":"2003","journal-title":"Prog. Polym. Sci."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2943","DOI":"10.1021\/cm000506g","article-title":"Structure and properties of poly (vinyl alcohol)\/Na+ montmorillonite nanocomposites","volume":"12","author":"Strawhecker","year":"2000","journal-title":"Chem. Mater."},{"key":"ref_35","unstructured":"(2025). Standard Test Method for Swell Index of Clay Mineral Component of Geosynthetic Clay Liners (Standard No. ASTM D5890)."},{"key":"ref_36","unstructured":"Arya, R. (2010). Drying of Thin Film Polymer Coating: Theories, Experiments and Optimization. [Ph. D. Thesis, Indian Institute of Technology Bombay]."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"334","DOI":"10.1346\/CCMN.2004.0520308","article-title":"Adsorption of poly (vinyl alcohol) on montmorillonite","volume":"52","author":"Ferreiro","year":"2004","journal-title":"Clays Clay Miner."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1346\/CCMN.1982.0300101","article-title":"Clay-polymer interactions: Summary and perspectives","volume":"30","author":"Theng","year":"1982","journal-title":"Clays Clay Miner."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Ba\u010dov\u00e1, P., Li, W., Behbahani, A.F., Burkhart, C., Poli\u0144ska, P., Doxastakis, M., and Harmandaris, V. (2021). Coupling between polymer conformations and dynamics near amorphous silica surfaces: A direct insight from atomistic simulations. Nanomaterials, 11.","DOI":"10.3390\/nano11082075"},{"key":"ref_40","unstructured":"Theng, B.K.G. (2012). Formation and Properties of Clay-Polymer Complexes, Elsevier."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Chang, S.-H. (1992). Effect of Polymer Adsorption on the Rheology and Stability of Suspensions, State University of New York at Buffalo.","DOI":"10.1122\/1.550345"},{"key":"ref_42","first-page":"101","article-title":"Optical Characterization of Silver Doped Poly (Vinyl Alcohol) Films","volume":"64","author":"Jabbar","year":"2010","journal-title":"J. Ark. Acad. Sci."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1016\/j.msec.2007.10.088","article-title":"FTIR spectroscopy characterization of poly (vinyl alcohol) hydrogel with different hydrolysis degree and chemically crosslinked with glutaraldehyde","volume":"28","author":"Mansur","year":"2008","journal-title":"Mater. Sci. Eng. C"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0927-796X(00)00012-7","article-title":"Polymer-layered silicate nanocomposites: Preparation, properties and uses of a new class of materials","volume":"28","author":"Alexandre","year":"2000","journal-title":"Mater. Sci. Eng. R Rep."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1071\/SR9640046","article-title":"The reaction of polyvinyl alcohol with montmorillonite","volume":"2","author":"Emerson","year":"1964","journal-title":"Soil Res."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"647","DOI":"10.1016\/0095-8522(63)90058-8","article-title":"Adsorption of polyvinyl alcohols by montmorillonite","volume":"18","author":"Greenland","year":"1963","journal-title":"J. Colloid Sci."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"140724","DOI":"10.1016\/j.colsurfa.2026.140724","article-title":"Coupled effects of water content and polyvinyl alcohol modification on the microstructure and mechanical behavior of montmorillonite","volume":"745","author":"Zheng","year":"2026","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"418","DOI":"10.1016\/j.colsurfa.2018.09.006","article-title":"Application of Validated Protocols to Characterize Size and Zeta Potential of Dispersed Materials using Light Scattering Methods","volume":"560","author":"Varenne","year":"2018","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1016\/j.partic.2010.01.003","article-title":"Effect of nanoparticle concentration on zeta-potential measurement results and reproducibility","volume":"8","author":"Tantra","year":"2010","journal-title":"Particuology"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"8000","DOI":"10.1021\/ma9603488","article-title":"Polymer melt intercalation in organically-modified layered silicates: Model predictions and experiment","volume":"30","author":"Vaia","year":"1997","journal-title":"Macromolecules"},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Corti, A., Cristiano, F., Solaro, R., and Chiellini, E. (2003). Biodegradable hybrid polymeric materials based on lignin and synthetic polymers. Biodegradable Polymers and Plastics, Springer.","DOI":"10.1007\/978-1-4419-9240-6_10"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"4259","DOI":"10.1021\/ma052647f","article-title":"Study of intercalation and exfoliation processes in polymer nanocomposites","volume":"39","author":"Bousmina","year":"2006","journal-title":"Macromolecules"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1119","DOI":"10.1016\/j.progpolymsci.2008.07.008","article-title":"A review on polymer\u2013layered silicate nanocomposites","volume":"33","author":"Pavlidou","year":"2008","journal-title":"Prog. Polym. Sci."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1002\/adma.19960080104","article-title":"Polymer layered silicate nanocomposites","volume":"8","author":"Giannelis","year":"1996","journal-title":"Adv. Mater."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1208\/s12249-017-0836-8","article-title":"Experimental Studies and Modeling of the Drying Kinetics of Multicomponent Polymer Films","volume":"19","author":"Velaga","year":"2018","journal-title":"AAPS PharmSciTech"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1007\/BF02914075","article-title":"Rheology and structure of aqueous bentonite-polyvinyl alcohol dispersions","volume":"29","author":"Atici","year":"2006","journal-title":"Bull. Mater. Sci."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1016\/0169-1317(88)90033-6","article-title":"Rheological properties of sodium montmorillonite dispersions","volume":"3","author":"Brandenburg","year":"1988","journal-title":"Appl. Clay Sci."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1122\/1.549853","article-title":"Analysis of linear viscoelasticity of a crosslinking polymer at the gel point","volume":"30","author":"Winter","year":"1986","journal-title":"J. Rheol."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"4772","DOI":"10.1103\/PhysRevA.42.4772","article-title":"Scaling behavior of the elastic properties of colloidal gels","volume":"42","author":"Shih","year":"1990","journal-title":"Phys. Rev. A"},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"852","DOI":"10.1021\/ma000565f","article-title":"A rheological study on the kinetics of hybrid formation in polypropylene nanocomposites","volume":"34","author":"Galgali","year":"2001","journal-title":"Macromolecules"}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/18\/16\/2025\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T08:25:26Z","timestamp":1787300726000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/18\/16\/2025"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,21]]},"references-count":60,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["polym18162025"],"URL":"https:\/\/doi.org\/10.3390\/polym18162025","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,21]]}}}