Chapter 90: Cloud experiment

　　 Xu Qiu has a degree specialized course "Nanomaterials" on Wednesday morning, and another elective course on Friday morning.
　　 In addition, this semester also has a "Production Practice", but this course is not taken every week, and the teaching content is usually arranged by the college system in the middle of the semester.
　　 usually visit factories, workshops, production lines, etc. The teaching content of the three majors is different, and lasts almost half a day to one day.
　　 Compared with undergraduates, postgraduate courses will be much less. Undergraduates need to take about 150 credits, while masters only need more than 30 credits, and doctors only need less than 20 credits.
　　 Chen Wanqing basically completed the courses in the first year of her PhD, so there will be no courses this semester.
　　 Therefore, she went to the Zhangjiang campus on Wednesday morning, and Xu Qiu did not leave until lunch.
　　……
　　 Room A501.
　　 Xu Qiu walked in and saw Chen Wanqing lying on the sofa to rest, so he teased:
　　 "Ms. Wei can't control this, is the senior sister being lazy?"
　　 "I'm not lazy, I did a lot of work in the morning," Chen Wanqing said, holding her finger tightly:
"The reaction of this time looks pretty good. I added a capping agent. The trimethyltinthiophene has been reacted, and the bromothiophene is now being capped, and I will help you with your reaction. All right;
　　Also, I also took out the glass instrument that was soaked in the alkali tank yesterday and cleaned it with an ultrasonic cleaner;
　　 In addition, the products from the Soxhlet extraction last time were the first batch of materials. I took them out and dried them in a vacuum oven. "
　　 "Senior sister has worked hard." Xu Qiu said.
　　 "Diligence can make up for the clumsiness, but when it comes to being lazy, Duan Yun is the master of paddling," Chen Wanqing said:
　　"He was in Zhangjiang before. For almost a week, he didn't do experiments, and he didn't know what he was doing with the computer every day.
I was thinking about what his group would do. I didn’t expect his group would say,
He did a synthesis experiment, but it didn’t succeed. It was speculated that the concentration was too high. Then he lowered the concentration and experimented again, but still Unsuccessful, so the next experiment intends to further reduce the concentration. ’
　　 If I hadn't been in Zhangjiang during that time, I would have been deceived by him. "
　　 "Duan Yun looks honest and would do something like this. This is the cloud experiment." Xu Qiu smiled.
　　 "It is not a cloud experiment. The result is actually his data last week, but he did not report it at the group meeting last week, but served as the report content of this group meeting." Chen Wanqing said.
　　 "Duan Yun is very witty, we can also learn from this method." Xu Qiu said.
　　 "If you don't get discovered, you'll be fine, if you are discovered, it will be miserable." Chen Wanqing said.
　　 "Senior sister, take a rest, I'll go to the laboratory to see."
　　 "Okay, pay attention to safety."
　　……
　　 Putting on protective equipment, Xu Qiu entered the A502 laboratory and walked to his fume hood.
There are two oil baths in 　　.
　　 One is equipped with a reaction vessel, and it is still being heated at 120 degrees Celsius, and it is undergoing a capping reaction of bromothiophene.
　　 This time the nitrogen ball is very firm, standing upright, and the size of a solid ball.
　　 It seems that after applying vacuum silicone grease, the airtightness of the system is enough to maintain for more than 24 hours.
The 　　 reaction flask is a two-necked flask, one of which is connected with a spherical condenser, and the other is plugged with a rubber stopper.
　　 You can use a syringe to inject medicines from the rubber stopper. For example, if the two capping agents used for capping are both liquid, they can be injected directly.
　　If it is a solid reagent, such as a catalyst, it needs to be dissolved in a solvent before injection.
　　 Of course, before injection, make sure there is no air in the syringe.
　　 Like an injection in a hospital, first spray some liquid to exhaust the air.
　　 After careful observation, Xu Qiu found that there was a ring of solid matter inside the reaction vessel.
　　 should be when the molecular weight of the high molecular polymer is relatively large, the solubility in the solution decreases, leading to its precipitation.
　　 Judging comprehensively, at least from the perspective of system air tightness and product molecular weight, the synthesis reaction of this second batch of PBT4T material is relatively successful.
　　 Xu Qiu looked at another oil bath again.
　　 This machine was used for Soxhlet extraction. The first batch of PBT4T material wrapped in filter paper in the extraction tube has been taken away by Chen Wanqing and dried in a vacuum, but the entire instrument has not been dismantled.
　　 It should be because the elder sister was too busy and didn't care about it. Of course, she might have forgotten.
　　 The color of the solution in the Erlenmeyer flask below is very dark, again indicating that the molecular weight of the first batch of materials is low.
　　 Xu Qiu poured the solvent in the Erlenmeyer flask into the waste liquid bucket, and then dismantled the device.
　　 By the way, after helping the senior sister's device also processed, he put all the glass instruments into the ultrasonic cleaner for cleaning.
　　 This time the glass instrument does not need to be soaked in the caustic tank first, because it is relatively clean, and this equipment will be used after the second batch of materials has been reacted.
　　……
　　 When Chen Wanqing came to the laboratory, she found that Xu Qiu had done the finishing work for her, and said:
　　 "The capping reaction time is almost ready, let's do the post-processing of the second batch of materials."
　　 Xu Qiu turned off the heating device of the oil bath, then lifted the reaction vessel above the oil level of the oil bath and waited for it to cool down naturally.
　　 "Sister~EbookFREE.me~ do you still vote for a new response today?" Xu Qiu said.
　　 "No, it's too tiring to experiment continuously," Chen Wanqing said:
　　 "Moreover, the performance of these two batches has not been tested yet. Let's make a few batches of devices with them, otherwise the team will have nothing to report next week."
"Ok."
　　 Xu Qiu used a disposable PE cup to receive methanol and prepare filter paper.
　　 After waiting for the reaction vessel to cool down to room temperature, dismantle the device, the solution with a disposable dropper, and drop it into methanol.
　　 Different from the post-processing of the first batch of products, this time the solution dripped, forming a small blue round cake, slowly falling into the bottom of the cup.
　　 And a dropper goes down, about two milliliters of solution is added to methanol, the methanol solution is still transparent, close to colorless.
　　 This shows that most of the products are precipitated in solid form, and the molecular weight of the product is very high.
　　 After absorbing the solution in the reaction bottle, there is a circle of solid product on the inner wall of the bottle, forming a ribbon-shaped film.
　　 Because this thing is already solid, there is no need to treat it with methanol.
　　 Xu Qiu directly took it out with a stainless steel spatula and threw it into the methanol solution.
　　 Then filter and let stand.
After 　　 was completed, Chen Wanqing was slightly excited and said:
　　 "This time the molecular weight is very high. It should be the most successful one since I did the synthesis reaction."
　　 Immediately, she changed her tone of voice again: "However, I read the literature and the molecular weight is not as high as possible."
　　 "Yes, although the higher the molecular weight, the better the photoelectric performance in theory, but the solubility will be reduced," Xu Qiu said:
　　 "If the solubility is low to a certain level and there is no way to form a film, no matter how good the performance is, it won't help."
　　 "I hope the performance of this batch of samples will be better."