https://tigerprints.clemson.edu/csrp/1018/thumbnail.jp

Chumanov, George

Edirisinghe, Dimuthu

Garcia, Astrid

Oliy, Bogdan

English

Clemson University: TigerPrints

Clemson University TigerPrints Chemistry Summer Research Program Student Works 7-2023 Stimuli-Responsive Self-Folding Bilayer Polymer Thin Films Astrid Garcia Dimuthu Edirisinghe Bogdan Oliy George Chumanov Follow this and additional works at: https://tigerprints.clemson.edu/csrp  Part of the Chemistry Commons ReferencesSubramani, N.K., Siddaramaiah, M.R. and Lee, J.H. eds., 2021. Polymer-Based Advanced Functional Composites for Optoelectronic and Energy Applications. Elsevier.Ionov, L.; Zakharchenko, S.; Stoychev, G.; Sperling, E. Soft Microorigami: Stimuli-Responsive Self-Folding Polymer Films. MRS Online Proc. Libr. 2011 14031 2011, 1403 (1), 202–206. https://doi.org/10.1557/OPL.2012.535.Gracias, D. H. Stimuli Responsive Self-Folding Using Thin Polymer Films. Curr. Opin. Chem. Eng. 2013, 2 (1), 112–119. https://doi.org/10.1016/J.COCHE.2012.10.003.Stimuli-Responsive Self-Folding Bilayer Polymer Thin FilmsAstrid Garcia1, Dimuthu Edirisinghe1, Bogdan Oliy2, George Chumanov1. Department of Chemistry, Biosystems Research Complex, Clemson, SC 29634.Teflon coated Aluminum SubstrateSpin coat the first polymer layer1600μL ofPolymer solution- 12.5 w%First polymer LayerSecond Polymer Bilayer• Dry for 1 hr• Then deposit the second polymer•  Spin coat againBilayer polymer can be peeled off from the substrateRight after applying pressure• Dry for 1 hr• Apply pressure 1000 PSI•  for 30. minCan polymers be used for artificial muscle?Bilayer polymer films basically respond to an external stimulus by changing their physical and chemical properties such as heat, water, ionic strength, pressure, and vapors. The concept of the polymer bilayer is similar to the bimetallic strip, which uses two metals with different thermal expansion coefficients and exhibits bending movements due to the unequal expansion of one metal layer. Well-adhered polymer bilayers should be designed to make self-folding structures. One polymer layer should be inactive or comparatively less active toward the particular stimulus to obtain the reversible folding and unfolding caused by swelling/dwelling or expansion/shrinking of the one polymer layer compared to the other. This phenomenon can be achieved by using different polymers with different functional groups. Vapor In outHexane PVP PSCyclohexane PVP PSToluene PVP PSIsopropyl alcohol PVP PSEthyl acetate PVP PSDI water PS PVPTemp. In Out Recovery time20 - - Straight 30PVP PS10 sec.40 5 min.55Complete recovery more than an hour7090100120 Did not recoverSpin Coating InstrumentAcknowledgmentsThank you to NSF grant number  #2050042 for the support and funding for this project. And Thank you to the chemistry department at Clemson University and Dr. Chumanov’s laboratory T. Burgess, M. Liyanage. • Polymers with different chemical and physical properties can be used to design bilayer polymer films with reversible responses to different stimuli. These polymer films can be further developed into artificial muscles.• In future work, develop conductive bilayer films using P4VP graphite composites.• Explore surface modification techniques to introduce pH-responsive groups.• Introduce crosslinking methods to control the solubility of polymers. • The microscopic image shows that the film has an overall thickness of 0.25mm. As expected, the polymer film responds to different temperatures.PS/P4VP  polymer films respond to different organic vapors.Interaction of P4VP with water molecules in water Interaction of P4VP with water molecules upon air-dryingPolymer 2Polymer 1The film is straight at room temperature (200C), then it started to bend when increasing the temperature as PS-out and P4VP-in because PS has a higher thermal expansion coefficient than P4VP. The film did not recover at 1200C because it passes the glass transition temperature (Tg) of polystyrene (1000C).Water ResponseOrganic VaporsTemperatureIntroductionExperimental MethodologyMicroscopic ImageRAMAN SpectroscopyConclusion and Future Works• Surprisingly, upon air-drying the film folds in the opposite direction leaving PS out and P4VP in. The hypothesis is that P4VP is shrinking due to the hydrogen bond interactions of bound water molecules with the pyridyl groups of the P4VP.• PS/P4VP in water and air-dried have reversible effects. Results show that in water  P4VP folds out and PS in. Suggesting that P4VP is swelling in water at a pH higher than 5. • The swelling is due to the hydrogen bond formation between pyridine groups and water molecules.Film in water Film air-dried Film with a spiral shape Folded Film Stimuli• Polystyrene swells in the presence of polar and non-polar vapors. • The film folds in a spiral shape with polar vapors.In this experiment, water, heat, and vapor stimuli will be studied for responsive self-folding bilayer Polystyrene (PS) and Poly(4-vinyl pyridine) (P4VP). These two polymers are being explored as a candidate to create artificial muscles from this bilayer structure.• Increasing the aspect ratio makes the film fold in a spiral shape versus the lower aspect ratio will make a curved shape.0.05mm • Swelling of the P4VP layer in the P4VP is due to the interactions of water molecules and the pyridyl group of the P4VP this can be clearly observed from the Raman spectroscopy. Dry P4VP under vacuum 993.3 cm -1, in water – 1002.5 cm-1. • The peak at 993.3 cm-1 corresponds to the vibrational mode of the pyridyl nitrogen.• Vacuum drying brings the peak at 1002.5 cm-1 back to the initial position at 993.3 cm-1. 

Stimuli-Responsive Self-Folding Bilayer Polymer Thin Films

https://tigerprints.clemson.edu/cgi/viewcontent.cgi?article=1018&context=csrp

Stimuli-Responsive Self-Folding Bilayer Polymer Thin Films

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