I Have a Research Support System

Next, elemental analysis of the polymeric donor material is performed.

Xu Qiu's five materials mainly contain carbon, hydrogen, nitrogen, sulfur, and fluorine.

Ideally, it only contains these five elements, but in fact, in the polymerization reaction, there must be unreacted trimethyltin or bromine end groups, so there will be traces of bromine, tin and other elements remaining in the product.

The elemental analyzer reserved in the school is tested by the combustion method.

Its basic working principle is that under the action of the composite catalyst, the sample is oxidized and burned at high temperature to obtain gaseous combustion products, and then the element content in the sample is reversed by detecting the combustion products.

Specifically, the material undergoes high-temperature oxidation and combustion to generate nitrogen, nitrogen oxides, carbon dioxide, sulfur dioxide, and water.

Driven by the carrier gas, these combustion products enter the separation and detection unit.

The adsorption column in the detection unit can adsorb and retain non-nitrogen compounds.

Nitrogen oxides are determined after reduction to nitrogen gas.

The oxides of other elements are separated and determined in the order of carbon, hydrogen and sulfur through the adsorption and analysis of the adsorption/desorption column.

With this method, halogens such as fluorine and bromine are difficult to detect, and metal tin is also difficult to detect, and only the proportions of carbon, hydrogen, nitrogen, and sulfur in the molecule can be obtained.

Like nuclear magnetic resonance, elemental analysis is also a sample test, but it does not require special sample preparation, only the original solid sample needs to be prepared.

"Xu Qiu, do you still have many polymer samples left?" Chen Wanqing frowned as she prepared the samples in the glove box, "I'm almost running out."

"You still have about 20 to 30 milligrams, why are you nervous?" Xu Qiu leaned over and said:

"The most insoluble P2FBT4T-2BO material I had before had an extremely low yield, only more than 30 mg.

I turned the bottle upside down and duang for a long time, and the bottom of the bottle was cleaned before I came up with this sample.

There are not any left now, and I will go to Zhangjiang to make up for a few reactions in the future. "

"Hmm..." Chen Wanqing stared at the reagent bottle in her hand, hesitated to speak.

"Sister, what's wrong?" Xu Qiu asked.

After hesitating for a while, she seemed to have made up her mind and said:

"I, I want to ask you to help me synthesize a batch of materials.

The reaction you voted for me before was that the ratio of the two A units was 7:3, and the resulting synthetic product had the highest device efficiency.

I am a little uncertain now, whether it is the 7:3 material itself that has good performance, or because the other two materials I synthesized, 3:7 and 5:5, have poor performance. "

"Is that so." Xu Qiu began to analyze:

When dealing with the synthesis reaction before, the two carried out it together. He also observed other products synthesized by himself and her, and it seemed that there was no problem.

In addition, the yield of the material, as well as the molecular weight data are also no problem.

From this point of view, theoretically, the performance differences of the three materials should have little to do with whether they are synthesized by themselves.

However, the experimenter responsible for the synthesis experiment is also considered as an experimental variable.

It is not difficult to vote for three responses for her to eliminate the influence of this variable, it just takes more time.

"No problem, leave it to me." Xu Qiu didn't think for long:

"However, after the light source test is finished, I will get all the experimental data and go to Zhang Jiang to write articles and do synthesis at the same time, and I can also teach Han Jiaying by the way."

"Okay." Chen Wanqing immediately smiled.

"By the way, the light source will be tested next week. This time it won't be overnight." Xu Qiu said.

"It's a good thing you reminded me. I almost forgot to ask Mr. Wei for a safety audit of the light source. The time is next Thursday during the daytime." Chen Wanqing said.

"Then do you want to bring Han Jiaying with you this time?" Xu Qiu asked.

"Go and ask to see if she is free." Chen Wanqing said.

...

At this time, Han Jiaying was sitting at the desk, holding a book and reading it carefully.

Xu Qiu found that this school girl was even more diligent than when he first joined the research group. She worked six days a week, and basically could see her four or five days.

She was already familiar with everyone in the lab, and Wu Feifei occasionally asked her for help, but mainly to help Xu Qiu and the others with their experiments.

Now she has learned the entire device preparation process.

Although not very skilled, it is no problem to operate independently, prepare and test a batch of devices.

As for other representation methods, they have not been studied yet.

As if sensing someone approaching, she raised her head, just in time to meet Xu Qiu's gaze.

"Han Jiaying, are you free next Thursday?"

"Next Thursday, I don't have any classes. I'll be free all day." Han Jiaying tilted her head, wondering:

"Brother, what do you want to do?"

"It's like this. Next Thursday, from 9:00 am to 9:00 pm, Chen Wanqing and I will go to the Shanghai Synchrotron Radiation Light Source for testing," Xu Qiu said:

"If you are free, you can go there with us, the location is Zhang Jiang's side.

The scheduled test time is twelve hours, but if all goes well, the test will end early. "

"So you asked me to do an experiment," Han Jiaying nodded and said, "Of course."

"Okay, first you have to register an account, and then conduct a security test. You can search the answers to the test questions online directly, and finally take a photo of the user number and record it."

After speaking, Xu Qiu helped her open the website of the light source, guided him to start the safety test, and then used a USB flash drive to copy the information he had consulted before, about the test principle of grazing incidence X-ray diffraction.

...

in a few days.

Xu Qiu got the elemental analysis and nuclear magnetic resonance spectrum data from the sample sent before.

Among them, the elemental analysis data is relatively simple, and the percentage content of carbon, hydrogen, nitrogen, and sulfur elements in the material is directly obtained, and no further data processing is required.

Xu Qiu compared the theoretical and detected percentages of each element in each material.

Overall, the errors of the four elements are not large, about 1-2%, which shows that the synthesis reaction is relatively successful.

As for the NMR spectrum, the sample signal is obvious in the hydrogen spectrum, but only the obvious solvent signal can be seen in the carbon spectrum, and the sample signal is very weak and can hardly be read.

Of course, this is also expected.

The processing of H NMR data is not difficult.

Import the data file into the analysis software, first use the signal peak of the deuterated chloroform solvent to calibrate the chemical shift of hydrogen, and then integrate the signal peak at each chemical shift to obtain the hydrogen content at the corresponding chemical shift.

However, analyzing this data is difficult.

The main reason is that the tested sample is a polymer, in which the chemical environment of hydrogen atoms is very complex, and the signal peaks obtained are mostly broad peaks, and it is difficult to judge the specific affiliation of hydrogen.

For such data, it is only necessary to mark the position of the peak, the number of multiple peaks, and the number of corresponding hydrogen atoms, and list the data.

Now only the data of the light source is missing, and victory is at hand.