TAILORING IONIC CONDUCTIVITY OF CHITOSAN FILMS THROUGH CONTROLLED LACTIC ACID INCORPORATION

Year 2025, Volume: 13 Issue: 3, 880 - 891, 01.09.2025

Doğa Doğanay

https://doi.org/10.36306/konjes.1678776

Abstract

Chitosan, a biodegradable and biocompatible biopolymer, is widely utilized due to its excellent film-forming capability and versatile applicability in various industries, including food packaging, pharmaceuticals, agriculture, and bioelectronics. This study investigates the influence of lactic acid concentration (2 wt%, 4 wt%, and 6 wt%) on the structural, thermal, and electrochemical properties of chitosan films. Films were prepared by dissolving chitosan in lactic acid solutions and casting them via solvent casting. Structural properties were characterized using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), thermal stability was analyzed by thermogravimetric analysis (TGA), and electrochemical properties were examined through ionic conductivity and capacitance measurements. The results reveal that increasing lactic acid concentration enhances ionic conductivity and areal capacitance of the chitosan films. At the highest lactic acid content (6 wt%), the films exhibited an ionic conductivity of 2.6 × 10⁻⁴ S/cm and an areal capacitance of 7.14 µF/cm² at 100 Hz. The results demonstrate the high potential of chitosan films for use in flexible energy storage systems, capacitive sensors and implantable bioelectronic devices.

Keywords

Chitosan Films , Lactic Acid , Ionic Conductivity

Ethical Statement

The authors declare that the study complies with all applicable laws and regulations and meets ethical standards.

Thanks

Melih Ogeday Cicek is gratefully acknowledged for his help with electrochemical measurements and consequent interpretation thereof.

References

• J. Lv, X. Lv, M. Ma, D.-H. Oh, Z. Jiang, and X. Fu, “Chitin and chitin-based biomaterials: A review of advances in processing and food applications,” Carbohydr Polym, vol. 299, p. 120142, Jan. 2023, doi: 10.1016/j.carbpol.2022.120142.
• J. Wang and S. Zhuang, “Chitosan-based materials: Preparation, modification and application,” J Clean Prod, vol. 355, p. 131825, Jun. 2022, doi: 10.1016/j.jclepro.2022.131825.
• S. Peers, A. Montembault, and C. Ladavière, “Chitosan hydrogels for sustained drug delivery,” Journal of Controlled Release, vol. 326, pp. 150–163, Oct. 2020, doi: 10.1016/j.jconrel.2020.06.012.
• U. Garg, S. Chauhan, U. Nagaich, and N. Jain, “Current Advances in Chitosan Nanoparticles Based Drug Delivery and Targeting,” Adv Pharm Bull, vol. 9, no. 2, pp. 195–204, Jun. 2019, doi: 10.15171/apb.2019.023.
• T. Dai, M. Tanaka, Y.-Y. Huang, and M. R. Hamblin, “Chitosan preparations for wounds and burns: antimicrobial and wound-healing effects,” Expert Rev Anti Infect Ther, vol. 9, no. 7, pp. 857–879, Jul. 2011, doi: 10.1586/eri.11.59.
• H. Wang, J. Qian, and F. Ding, “Emerging Chitosan-Based Films for Food Packaging Applications,” J Agric Food Chem, vol. 66, no. 2, pp. 395–413, Jan. 2018, doi: 10.1021/acs.jafc.7b04528.
• F. Demir, G. Gökşen, And D. Demir Karakuş, “Effect Of Orange Peel Essentıal Oıl On The Propertıes Of Chıtosan: Gelatın Casted Fılms Prepared For Actıve Packagıng,” Konya Journal of Engineering Sciences, Vol. 11, no. 3 pp. 668–677, May 2023, doi: 10.36306/konjes.1225056.
• A. Kazan And F. Demirci, “Olıve Leaf Extract Incorporated Chıtosan Fılms For Actıve Food Packagıng,” Konya Journal Of Engineering Sciences, Vol. 11, no. 4, Pp. 1061–1072, Dec. 2023, Doi: 10.36306/Konjes.1310528.
• K. Xing, X. Zhu, X. Peng, and S. Qin, “Chitosan antimicrobial and eliciting properties for pest control in agriculture: a review,” Agron Sustain Dev, vol. 35, no. 2, pp. 569–588, Apr. 2015, doi: 10.1007/s13593-014-0252-3.
• S. Wu, S. Wu, X. Zhang, T. Feng, and L. Wu, “Chitosan-Based Hydrogels for Bioelectronic Sensing: Recent Advances and Applications in Biomedicine and Food Safety,” Biosensors (Basel), vol. 13, no. 1, p. 93, Jan. 2023, doi: 10.3390/bios13010093.
• B. Ronnasi, S. P. McKillop, M. Ourabi, M. Perry, H. A. Sharp, and B. H. Lessard, “Chitosan-Based Electronics: The Importance of Acid Strength and Plasticizing Additives on Device Performance,” ACS Appl Mater Interfaces, Nov. 2024, doi: 10.1021/acsami.4c10508.
• C. Hu, L. Wang, S. Liu, X. Sheng, and L. Yin, “Recent Development of Implantable Chemical Sensors Utilizing Flexible and Biodegradable Materials for Biomedical Applications,” ACS Nano, vol. 18, no. 5, pp. 3969–3995, Feb. 2024, doi: 10.1021/acsnano.3c11832.
• J. Zou, K. Zhang, and Q. Zhang, “Giant Humidity Response Using a Chitosan-Based Protonic Conductive Sensor,” IEEE Sens J, vol. 16, no. 24, pp. 8884–8889, Dec. 2016, doi: 10.1109/JSEN.2016.2616484.
• M. Zhang, A. Smith, and W. Gorski, “Carbon Nanotube−Chitosan System for Electrochemical Sensing Based on Dehydrogenase Enzymes,” Anal Chem, vol. 76, no. 17, pp. 5045–5050, Sep. 2004, doi: 10.1021/ac049519u.
• S. Wu et al., “Recent Advances in Chitosan-Based Hydrogels for Flexible Wearable Sensors,” Jan. 01, 2023, Multidisciplinary Digital Publishing Institute (MDPI). doi: 10.3390/chemosensors11010039.
• S. (Gabriel) Kou, L. Peters, and M. Mucalo, “Chitosan: A review of molecular structure, bioactivities and interactions with the human body and micro-organisms,” Carbohydr Polym, vol. 282, p. 119132, Apr. 2022, doi: 10.1016/j.carbpol.2022.119132.
• C. Qiao, X. Ma, X. Wang, and L. Liu, “Structure and properties of chitosan films: Effect of the type of solvent acid,” LWT, vol. 135, p. 109984, Jan. 2021, doi: 10.1016/j.lwt.2020.109984.
• C. Caner, P. J. Vergano, and J. L. Wiles, “Chitosan Film Mechanical and Permeation Properties as Affected by Acid, Plasticizer, and Storage,” J Food Sci, vol. 63, no. 6, pp. 1049–1053, Nov. 1998, doi: 10.1111/j.1365-2621.1998.tb15852.x.
• W. Zhang et al., “The role of organic acid structures in changes of physicochemical and antioxidant properties of crosslinked chitosan films,” Food Packag Shelf Life, vol. 31, p. 100792, Mar. 2022, doi: 10.1016/j.fpsl.2021.100792.
• M. G. Goñi, B. Tomadoni, S. I. Roura, and M. del R. Moreira, “Lactic acid as potential substitute of acetic acid for dissolution of chitosan: preharvest application to Butterhead lettuce,” J Food Sci Technol, vol. 54, no. 3, pp. 620–626, Mar. 2017, doi: 10.1007/s13197-016-2484-5.
• K. M. Kim, J. H. Son, S.-K. Kim, C. L. Weller, and M. A. Hanna, “Properties of Chitosan Films as a Function of pH and Solvent Type,” J Food Sci, vol. 71, no. 3, pp. E119–E124, Jun. 2006, doi: 10.1111/j.1365-2621.2006.tb15624.x.
• X. Qu, A. Wirsén, and A.-C. Albertsson, “Effect of lactic/glycolic acid side chains on the thermal degradation kinetics of chitosan derivatives,” Polymer (Guildf), vol. 41, no. 13, pp. 4841–4847, Jun. 2000, doi: 10.1016/S0032-3861(99)00704-1.
• X. Dou, Q. Li, Q. Wu, L. Duan, S. Zhou, and Y. Zhang, “Effects of lactic acid and mixed acid aqueous solutions on the preparation, structure and properties of thermoplastic chitosan,” Eur Polym J, vol. 134, p. 109850, Jul. 2020, doi: 10.1016/j.eurpolymj.2020.109850.
• D. G. Mackanic et al., “Decoupling of mechanical properties and ionic conductivity in supramolecular lithium ion conductors,” Nat Commun, vol. 10, no. 1, p. 5384, Nov. 2019, doi: 10.1038/s41467-019-13362-4.
• J. Chattopadhyay, T. S. Pathak, and D. M. F. Santos, “Applications of Polymer Electrolytes in Lithium-Ion Batteries: A Review,” Polymers (Basel), vol. 15, no. 19, p. 3907, Sep. 2023, doi: 10.3390/polym15193907.
• L. Segal, J. J. Creely, A. E. Martin, and C. M. Conrad, “An Empirical Method for Estimating the Degree of Crystallinity of Native Cellulose Using the X-Ray Diffractometer,” Textile Research Journal, vol. 29, no. 10, pp. 786–794, Oct. 1959, doi: 10.1177/004051755902901003.
• P. Naito, Y. Ogawa, D. Sawada, Y. Nishiyama, T. Iwata, and M. Wada, “X‐ray crystal structure of anhydrous chitosan at atomic resolution,” Biopolymers, vol. 105, no. 7, pp. 361–368, Jul. 2016, doi: 10.1002/bip.22818.
• K. Ogawa and T. Yui, “Effect of Explosion on the Crystalline Polymorphism of Chitin and Chitosan,” Biosci Biotechnol Biochem, vol. 58, no. 5, pp. 968–969, Jan. 1994, doi: 10.1271/bbb.58.968.
• R. J. Samuels, “Solid state characterization of the structure of chitosan films,” Journal of Polymer Science: Polymer Physics Edition, vol. 19, no. 7, pp. 1081–1105, Jul. 1981, doi: 10.1002/pol.1981.180190706.
• I. Kondratowicz et al., “Impact of Lactic Acid and Genipin Concentration on Physicochemical and Mechanical Properties of Chitosan Membranes,” J Polym Environ, vol. 31, no. 3, pp. 1221–1231, Mar. 2023, doi: 10.1007/s10924-022-02691-z.
• X. Qu, A. Wirson, and A.-C. Albertsson, “Synthesis and characterization of pH-sensitive hydrogels based on chitosan andD,L-lactic acid,” J Appl Polym Sci, vol. 74, no. 13, pp. 3193–3202, Dec. 1999, doi: 10.1002/(SICI)1097-4628(19991220)74:13<3193::AID-APP23>3.0.CO;2-V.
• C. Paluszkiewicz, E. Stodolak, M. Hasik, and M. Blazewicz, “FT-IR study of montmorillonite–chitosan nanocomposite materials,” Spectrochim Acta A Mol Biomol Spectrosc, vol. 79, no. 4, pp. 784–788, Aug. 2011, doi: 10.1016/j.saa.2010.08.053.
• A. Pawlak and M. Mucha, “Thermogravimetric and FTIR studies of chitosan blends,” Thermochim Acta, vol. 396, no. 1–2, pp. 153–166, Feb. 2003, doi: 10.1016/S0040-6031(02)00523-3.
• M. Darder, M. Colilla, and E. Ruiz-Hitzky, “Chitosan–clay nanocomposites: application as electrochemical sensors,” Appl Clay Sci, vol. 28, no. 1–4, pp. 199–208, Jan. 2005, doi: 10.1016/j.clay.2004.02.009.
• M. L. Duarte, M. C. Ferreira, M. R. Marvão, and J. Rocha, “An optimised method to determine the degree of acetylation of chitin and chitosan by FTIR spectroscopy,” Int J Biol Macromol, vol. 31, no. 1–3, pp. 1–8, Dec. 2002, doi: 10.1016/S0141-8130(02)00039-9.
• Y. Shigemasa, H. Matsuura, H. Sashiwa, and H. Saimoto, “Evaluation of different absorbance ratios from infrared spectroscopy for analyzing the degree of deacetylation in chitin,” Int J Biol Macromol, vol. 18, no. 3, pp. 237–242, Apr. 1996, doi: 10.1016/0141-8130(95)01079-3.
• C. Qiao, X. Ma, X. Wang, and L. Liu, “Structure and properties of chitosan films: Effect of the type of solvent acid,” LWT, vol. 135, p. 109984, Jan. 2021, doi: 10.1016/j.lwt.2020.109984.
• K. M. Kim, J. H. Son, S.-K. Kim, C. L. Weller, and M. A. Hanna, “Properties of Chitosan Films as a Function of pH and Solvent Type,” J Food Sci, vol. 71, no. 3, pp. E119–E124, Jun. 2006, doi: 10.1111/j.1365-2621.2006.tb15624.x.
• I. Kondratowicz et al., “Impact of Lactic Acid and Genipin Concentration on Physicochemical and Mechanical Properties of Chitosan Membranes,” J Polym Environ, vol. 31, no. 3, pp. 1221–1231, Mar. 2023, doi: 10.1007/s10924-022-02691-z.
• K. Lewandowska, “Miscibility and thermal stability of poly(vinyl alcohol)/chitosan mixtures,” Thermochim Acta, vol. 493, no. 1–2, pp. 42–48, Sep. 2009, doi: 10.1016/j.tca.2009.04.003.
• J. M. F. Pavoni, C. L. Luchese, and I. C. Tessaro, “Impact of acid type for chitosan dissolution on the characteristics and biodegradability of cornstarch/chitosan based films,” Int J Biol Macromol, vol. 138, pp. 693–703, Oct. 2019, doi: 10.1016/j.ijbiomac.2019.07.089.
• I. Quıjadagarrıdo, V. Iglesıasgonzalez, J. Mazonarechederra, And J. Barralesrıenda, “The role played by the interactions of small molecules with chitosan and their transition temperatures. Glass-forming liquids: 1,2,3-Propantriol (glycerol),” Carbohydr Polym, vol. 68, no. 1, pp. 173–186, Mar. 2007, doi: 10.1016/j.carbpol.2006.07.025.
• J. Khouri, A. Penlidis, and C. Moresoli, “Heterogeneous method of chitosan film preparation: Effect of multifunctional acid on film properties,” J Appl Polym Sci, vol. 137, no. 18, May 2020, doi: 10.1002/app.48648.
• W. Tang et al., “Facile pyrolysis synthesis of ionic liquid capped carbon dots and subsequent application as the water-based lubricant additives,” J Mater Sci, vol. 54, no. 2, pp. 1171–1183, Jan. 2019, doi: 10.1007/s10853-018-2877-0.
• M. L. Amorim et al., “Physicochemical Aspects of Chitosan Dispersibility in Acidic Aqueous Media: Effects of the Food Acid Counter-Anion,” Food Biophys, vol. 11, no. 4, pp. 388–399, Dec. 2016, doi: 10.1007/s11483-016-9453-4.
• J. Wan, J. Zhang, J. Yu, and J. Zhang, “Cellulose Aerogel Membranes with a Tunable Nanoporous Network as a Matrix of Gel Polymer Electrolytes for Safer Lithium-Ion Batteries,” ACS Appl Mater Interfaces, vol. 9, no. 29, pp. 24591–24599, Jul. 2017, doi: 10.1021/acsami.7b06271.
• Y. Ran, Z. Yin, Z. Ding, H. Guo, and J. Yang, “A polymer electrolyte based on poly(vinylidene fluoride-hexafluoropylene)/hydroxypropyl methyl cellulose blending for lithium-ion battery,” Ionics (Kiel), vol. 19, no. 5, pp. 757–762, May 2013, doi: 10.1007/s11581-012-0808-7.
• M. Wu et al., “A sustainable chitosan-zinc electrolyte for high-rate zinc-metal batteries,” Matter, vol. 5, no. 10, pp. 3402–3416, Oct. 2022, doi: 10.1016/j.matt.2022.07.015.
• X. Jia et al., “A Biodegradable Thin-Film Magnesium Primary Battery Using Silk Fibroin–Ionic Liquid Polymer Electrolyte,” ACS Energy Lett, vol. 2, no. 4, pp. 831–836, Apr. 2017, doi: 10.1021/acsenergylett.7b00012.
• J. Xu, R. Jin, X. Ren, and G. Gao, “A wide temperature-tolerant hydrogel electrolyte mediated by phosphoric acid towards flexible supercapacitors,” Chemical Engineering Journal, vol. 413, p. 127446, Jun. 2021, doi: 10.1016/j.cej.2020.127446.
• J. Zeng, L. Dong, W. Sha, L. Wei, and X. Guo, “Highly stretchable, compressible and arbitrarily deformable all-hydrogel soft supercapacitors,” Chemical Engineering Journal, vol. 383, p. 123098, Mar. 2020, doi: 10.1016/j.cej.2019.123098.
• M. O. Cicek et al., “Ultra‐Sensitive Bio‐Polymer Iontronic Sensors for Object Recognition from Tactile Feedback,” Adv Mater Technol, vol. 8, no. 16, Aug. 2023, doi: 10.1002/admt.202300322.
• S. Li, J. Chu, B. Li, Y. Chang, and T. Pan, “Handwriting Iontronic Pressure Sensing Origami,” ACS Appl Mater Interfaces, vol. 11, no. 49, pp. 46157–46164, Dec. 2019, doi: 10.1021/acsami.9b16780.
• J. Zou, K. Zhang, and Q. Zhang, “Giant Humidity Response Using a Chitosan-Based Protonic Conductive Sensor,” IEEE Sens J, vol. 16, no. 24, pp. 8884–8889, Dec. 2016, doi: 10.1109/JSEN.2016.2616484.