Highly Water‐Soluble Rod–Coil Conjugated Block Copolymer for Efficient Humidity Sensor. Issue 16 (24th July 2019)

• Record Type: Journal Article
• Authors: Khawas, Koomkoom; Daripa, Soumili; Kumari, Pallavi; Das, Santanu; Dey, Ratan Kumar; Kuila, Biplab Kumar
• Is Part Of: Macromolecular chemistry and physics. Volume 220:Issue 16(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-07-24
• Subjects: block copolymers -- conjugated polymers -- humidity sensors -- proton conducting polymers; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.201900013
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract: In this report, the preparation of highly water‐soluble rod–coil conjugated block copolymer poly(3‐hexylthiophene)‐ b ‐polystyrenesulfonic acid (P3HT‐ b ‐PSSA) is demonstrated using a facile method with its moisture sensing properties. The block copolymer synthesis method comprises Kumada catalyst transfer polymerization and atom transfer radical polymerization from a bifunctional initiator followed by sulfonation of polystyrene using moderate reaction conditions. The polymerization results in the synthesis of well‐defined block copolymers with controllable block length. The successful synthesis of the block copolymer is studied by NMR and FTIR spectroscopy while optical and structural properties of the block copolymer are investigated using UV–vis, photoluminescence spectroscopy, XRD, and FESEM. In water, the block copolymer shows aggregated structure with crystalline core formed by rod‐like P3HT chain with absorption maxima at 558 nm, whereas in solid state the absorption maxima is blue shifted to 548 nm. The proton conductivity of the block copolymer P3HT‐ b ‐PSSA with ≈91% of PSSA (by weight) is measured from impedance study, and the values for bulk and grain conductivities are 5.25 × 10 −4 and 4.66 × 10 −6 S cm −1, respectively, at room temperature. The as‐synthesized block copolymer shows a very high water uptake with maximum ≈80% in comparison with its initial weight. The I–V measurement of the device made from block copolymer shows nonlinear, rectifying characteristic and the current increases with increase of relative humidity (RH%). The block copolymer device shows well‐correlated systemic and reversible resistance change with RH both in doped and undoped state. It is believed that the interesting and highly reversible moisture‐sensitive electronic properties of this block copolymer will be useful for the fabrication of moisture‐sensitive polymer‐based flexible electronic devices. Abstract : In this report, the synthesis of highly water‐soluble rod–coil conjugated block copolymer poly(3‐hexylthiophene)‐ b ‐polystyrenesulfonic acid (P3HT‐ b ‐PSSA) is demonstrated using a facile method with its moisture‐sensing properties. The synthesis method comprises Kumada catalyst transfer polymerization and atom transfer radical polymerization from a bifunctional initiator followed by sulfonation of polystyrene using moderate reaction condition.