Synthesis And Application Of Phenylboronic Acid-Substituted Polydiacetylene

Environmentally responsive conjugated polymers can convert external stimuli into photoelectric signals that are easy to observe and detect,and have been widely used in sensing and detection fields.Polydiacetylene(PDA)is a new type of environmentally responsive conjugated polymer.When it is stimulated by external environment,the blue-to-red transition phenomenon and the change of fluorescence generally occur.This makes PDA widely used in colorimetric and fluorescent sensors.The PDA with irreversible colorimetric transition seriously restricts its application in the field of sensing.Many researchers are committed to the preparation of PDA with reversible thermochromism.The main idea is to introduce ?-? stacking interaction,hydrogen bonding or electrostatic interaction at the end of the PDA side chain.At present,PDA still has the problems of narrow temperature range of reversible thermochromism and poor solvent resistance,and the color change mechanism of PDA in response to external stimuli is still not clear.In this paper,we synthesized phenylboronic acid-substituted PDA,by introducing covalent bonds between the PDA side groups to generate a crosslinked PDA,to achieve the purpose of PDA with reversible thermochromism and improve its solvent resistance,and studied the relationship between the degree of PDA crosslinking and its reversible thermochromism or its solvatochromism.The mechanism and influencing factors of PDA color change were systematically studied.We synthesized phenylboronic acid-substituted diacetylene derivatives.and prepared phenylboronic acid-substituted PDA film.The results showed that in the solvatochromic experiment.the greater of crosslinking degree of the phenylboronic acid-substituted PDA films,the smaller the change degree of blue to red under the same solvent stimuli.In the thermochromic experiment,the crosslinking degree of the phenylboronic acid-substituted PDA film is related to its reversible degree of thermochromism.The greater the crosslinking degree of the phenylboronic acid-substituted PDA film,the higher the upper limit of the temperature at which reversible thermochromism occurs.We built different sensor devices using inkjet printing technology and electrospinning technology.A pattern containing phenylboronic acid-substituted PDA was prepared by means of inkjet printing technology.The different crosslinking degree of the phenylboronic acid-substituted PDA in the pattern showed different degrees of solvochromism to the same solvent.When phenylboronic acid-substituted PDA in patterns have different degrees of crosslinking,the patterns show different degrees of reversible thermochromism after heat stimuli.The higher the degree of PDA crosslinking,the higher the corresponding reversible degrees of thermochromism.In addition,the micron composite fiber is constructed by means of electrostatic spinning technology,and it has different waveguide loss coefficients with or without crosslinking of phenylboronic acid-substituted PDA in fiber.Preparing crosslinked PDA by introducing a covalent bond between the PDA side groups require PDA with reversible thermochromism provides direction for the preparation of new reusable PDA sensors,and this crosslinked PDA has very good application prospects.