TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): The preparation of (I), comprises (a) adding 29 g 3-bromo-2-thiophenecarboxylic acid, 35 g dicyclohexylcarbodiimide and 5.6 g 4-dimethylaminopyridine into 280 ml dichloromethane under an inert atmosphere, then adding 36 g 2-ethylhexanol, and stirring at room temperature for 16 hours, then pouring the mixture into water, extracting with diethyl ether twice, combining the organic phases and drying over anhydrous magnesium sulfate, removing the solvent, and eluting with mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 50:1 using silica gel column to obtain 40 g (90% yield) colorless viscous liquid intermediate (II), (b) dissolving 7.1 g (II) in 12.7 g chloromethyl ether at 0 degrees C, adding 10.5 g titanium tetrachloride in dropwise, and reacting at 50 degrees C for overnight, pouring the mixture into water after 15 hours, extracting with diethyl ether twice, combining organic phases and drying over anhydrous magnesium sulfate, removing the solvent, and eluting with mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 3:1 using silica gel column chromatography to obtain 3.8 g (41% yield) brown viscous liquid intermediate (III), (c) dissolving 2.75 g (III) in 100 ml dry methanol, heating to 60 degrees C, adding 0.51 g anhydrous sodium sulfide and stirring for 1 hour, concentrating the reaction solution, and eluting with petroleum ether using silica gel column chromatography to obtain 1.17 g (47% yield) light-yellow viscous liquid intermediate (IV), (d) dissolving (1.13 g, 3 mmol) intermediate (IV) in 20 ml tetrahydrofuran, adding 2M sodium hydroxide solution and refluxing for overnight, cooling to room temperature , adding dilute 2M hydrochloric acid to adjust pH to acidic, collecting organic phase and drying to obtain yellow solid powder intermediate (V), where (V) can be used directly without purification in the next step, (e) adding 8.6 g (V) into 50 ml quinoline, then adding 1.02 g copper powder, reacting at 200 degrees C for 2 hours, cooling to room temperature, adding dilute hydrochloric acid to neutralize, pouring the mixture into water and extracting twice with ether, then combining organic phases, drying over anhydrous magnesium sulfate, removing the solvent, eluting with petroleum ether using silica gel column to obtain 4.31 g (61% yield) bright-yellow solid intermediate (VI), (f) dissolving 1.55 g (VI) in 25 ml tetrahydrofuran under an inert atmosphere, adding 3.5 ml 2M lithium diisopropylamide, cooling to 0 degrees C and reacting for half an hour, then adding 0.79 g N-formylpiperidine, reacting at room temperature for 6 hours, pouring the reaction mixture into water, extracting twice with diethyl ether, combining organic phases, drying over anhydrous magnesium sulfate, removing the solvent, eluting with mixed solvent of petroleum ether and dichloromethane in a volume ratio of 5:1 using silica gel column to obtain 1.26 g (72%) bright-yellow solid intermediate (VII), then (g) adding 1 g (VII), 1.06 g isooctyl thioglycolate and 1.1 g potassium carbonate into 20 ml dimethylformamide, stirring for 18 hours at room temperature, pouring the reaction mixture into water, extracting with ether twice, combining organic phases, drying over anhydrous magnesium sulfate, removing the solvent, eluting with mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:1 using silica gel column to obtain 0.95 g (67% yield) bright-yellow liquid intermediate (VIII), (h) adding 0.51 g m-chloroperoxybenzoic acid and 1.04 g (VIII) into 20 ml ethyl acetate solution at -78 degrees C, heating to room temperature, and stirring to obtain an intermediate (IX), where (IX) can be used directly without purification in the next reaction step, (i) adding (IX) into 5 ml acetic anhydride, stirring at reflux temperature for half an hour, pouring the mixture into water, extracting with ether twice, combining organic phases, drying over anhydride magnesium sulfate, removing the solvent, eluting with mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:1 using silica gel column to obtain 0.45 g (43% yield) bright-yellow liquid intermediate (X), and (j) adding 0.71 g N-bromosuccinimide, 0.56 g (X) into 25 ml N,N-dimethylformamide at 0 degrees C under nitrogen atmosphere, stirring at 0 degrees C for 2 hours, then pouring the reaction mixture into water, extracting with ether twice, combining organic phases and drying over anhydrous magnesium sulfate, removing the solvent, eluting with petroleum ether using silica gel column to obtain 0.65 g (80% yield) bright-yellow liquid monomer (DTT3E). Preferred Components: The number average molecular weight of (I) is 1000-1000000, preferably 20000-200000.