Chapter 91: 2 batches of materials

　　 "The new materials we synthesize should also characterize their basic properties, such as molecular weight and elemental analysis." Xu Qiu said:
　　 "That's right, but it would be too troublesome to test it every time after the synthesis is finished. Generally, test the batch with the best performance." Chen Wanqing said:
　　" Make an appointment on the material department instrument sharing platform, first use gel chromatography GPC to test the molecular weight, in addition to nuclear magnetic resonance NMR, hydrogen spectrum, carbon spectrum, and element analysis.
　　Some materials can also be characterized by infrared spectroscopy and Raman spectroscopy, but our materials do not need it. "
　　 "The characterization of new materials is so troublesome." Xu Qiu exclaimed.
　　 "Yes, I published an article a few years ago. If it is to report a new material, it will not be published if it is not fully characterized," Chen Wanqing said:
　　"Now it is much more relaxed, and these characterization results are usually not put in the text for analysis, and just be given in the supporting information.
　　 By the way, I received the email a few days ago. The department can sign up for instrument training at the beginning of the semester. You can reply to the email to sign up. "
　　 "Are there?" Xu Qiu asked in confusion:
　　 "I had a class meeting yesterday, and I just checked my inbox, but I didn't see any related emails."
　　 Chen Wanqing thought for a while, and suddenly said: "I forgot that you are still an undergraduate. This training is for graduate students.
　　 But the problem is not big, anyway, if I am there, we can go together if I do anything. "
　　 After filtering the second batch of synthetic materials, the two put them in the Soxhlet extractor to start extraction.
　　 Then put the first batch of dried materials into the sealed tank where the monomer was previously stored for temporary storage.
　　 After confirming the safety of water, electricity and gas, close the laboratory.
　　…………
　　 The next day, the two came to Zhang Jiang's laboratory again.
　　The Soxhlet extraction of the second batch of materials has been completed, as long as it is dried in a vacuum oven.
　　 Compared with the oven in the laboratory, the vacuum oven is relatively small.
　　 The former is more than one meter in length, width and height, while the latter is about the size of a microwave oven.
　　The inside of the oven will release a lot of heat to maintain the temperature, so there is a certain degree of danger.
　　 On the one hand, accidental contact with the human body can cause burns, and on the other hand, there is a fire hazard.
　　Laboratory safety regulations stipulate that it is not allowed to stack items around the oven, especially combustible materials such as solvents, so it occupies a relatively large area.
　　 Fortunately, the Zhangjiang laboratory is very large, which is not a problem.
For 　　 vacuum oven, in addition to the heating function of an ordinary oven, it also integrates a vacuum function, which can be connected to a vacuum pump to vacuum its internal cabin.
　　In this way, there is no need to worry that the sample will react with oxygen under heating.
　　 And the lower the vacuum, the lower the boiling point of the solvent.
　　Using a vacuum oven can quickly dry solvents with a boiling point over 100 degrees Celsius at a lower temperature, such as 70 degrees Celsius.
　　 After putting the second batch of samples into the vacuum oven, the two returned to the A501 office.
　　 Today is a day of paddling.
　　 Zhangjiang Handan takes two hours to commute to and from work and four hours to wait for drying, while the experimental operation only takes 15 minutes.
　　 means that it took one day and only fifteen minutes of work.
　　 Chen Wanqing sat at the desk and used the computer to chase the drama. After Xu Qiu completed the one-hour daily literature reading task, he opened the starting point and read the novel.
　　 There is a senpai, and it is difficult for him to enter the simulation laboratory.
　　……
　　 Four hours later.
　　 The second batch of samples was dried, and Xu Qiu weighed its mass with a balance, which was more than 120 mg.
　　 The total mass of monomers charged was more than 160 mg.
　　 Calculating the yield, it is roughly 85%, which is already very high.
　　 The first batch of samples only obtained more than 60 mg, and the yield was less than 50%.
　　 When calculating the yield here, you cannot directly divide 120 by 160.
　　 The trimethyltin and bromine groups attached to the two ends of the monomer will fall off after the condensation reaction, and this part must be deducted.
　　 Therefore, the mass of the effective part of the monomer raw material is only about 140 mg.
　　 Xu Qiu used tweezers and weighing paper to carefully transfer the sample to the glass bottle, mark "PBT4T-2" with a marker, and then wrap the glass bottle with aluminum foil.
After 　　 is completed, bring both batches of samples and return to Handan campus.
　　 Although the monomer raw material is toxic, it becomes a polymer after synthesis, and the toxicity is almost zero.
　　 And the samples are still in bottles and packed in garbage bags, so it’s not a problem to take them on the school bus.
　　……
　　 In the evening, Xu Qiu "snatched" the glove box from Wu Feifei.
　　 He was not sure about the solubility of the product and what kind of solvent was better, so he tried two solvents, chloroform and chlorobenzene, and each prepared 1 ml of solution.
　　 Two batches of samples, two solvents, a total of four sets of solutions.
The concentration of 　　 polymer donor is 5 mg/ml (chloroform) and 8 mg/ml (chlorobenzene).
　　The acceptor material is PC[60]BM, and the mass ratio of donor to acceptor is 1:1.
　　 Obviously, it is impossible to continue making devices tonight. The solution can be stirred overnight. Xu Qiu did not adjust the temperature of the heating stage too high, but only adjusted it to 45 degrees Celsius.
　　 He also helped the senior sister to prepare four sets of solutions under the same conditions and put them on the heating and stirring table together.
　　 After all is finished, it is nine o'clock.
　　 Xu Qiu left the glove box and called Feifei Wu.
She glared at Xu Qiu and took over the glove box from him~EbookFREE.me~ Xu Qiu hurriedly slipped away. He was in a bad position. At that time, he moved with affection to understand the reason, and said that it would be completed in half an hour. Solution, but it took nearly an hour and a half.
　　 It takes a lot of time to weigh the polymer. The polymer will be adsorbed on the wall of the bottle and on the tweezers. It should be electrostatically adsorbed, which is difficult to grasp.
　　 Back to the desk, Xu Qiu invited the senior sister to run at night, and the other party readily agreed.
　　 This semester, the two will go out for a few laps together when they have time.
　　 Chen Wanqing couldn't catch his breath after running two steps at the very beginning, and now he can chat with Xu Qiu while running.
　　 After jogging for two kilometers, the two of them came to the lawn next to the first floor of the material, exercised their bodies and stretched the ligaments to relieve the muscle aches the next day.
　　 After exercising, Xu Qiu returned to the laboratory and went to the glove box to check the solution he prepared. It seemed that there was no problem.
　　 However, he once again caught Wu Feifei's eye.
　　Because Xu Qiu had class on Friday morning, he asked the senior sister to help him prepare a few substrates when he was making the device tomorrow before he left.
　　……
　　 went back to the dormitory and missed the opening of the student bathroom, so Xu Qiu had to take a shower again.
　　He entered the simulation laboratory, and his progress remained at the state of his last practice.
　　 A few days ago, he had been going to Zhangjiang to do synthesis, and he needed to stand for continuous experiments, and he had to spend an hour every day reading literature and exercising. At night, he had no energy, so he didn't continue experiments in the simulation laboratory.
　　 Although I paddled for a day today, Xu Qiu still found an excuse for himself:
　　 If you make the device tomorrow, you can get the result of the photoelectric performance. Let's wait for the result to come out.
　　 took a look, he withdrew from the simulation laboratory.