- Writing an introduction can be made easy by splitting it into three parts: the background, literature and objective(s).
- Your introduction should be relatively short accounting for 10% of your research article’s word count.
- Consider who your readers will be. Will they be experts in your field, laypeople or both? Once you know, begin adjusting your writing style accordingly.
- Don’t write a literature review. Choose only the reputable and reliable sources to refer to in your introduction.
- Decide how you present your objective. Will you present it as a question, hypothesis or by using infinitives?
In a research article, the introduction section comes after the abstract. If you want to know some handy tips on how to write an abstract then check out my blog ‘Writing an effective abstract’. The introduction section is probably the most neglected as it’s often seen more as a formality. But this goes back to telling a story.
If you’re watching a movie you’re often introduced to characters and given their background information so that the audience builds a connection with those onscreen characters. So, when something happens, good or bad, to those characters the audience cares. Similarly, an author has to set the scene for their readers and explain to them why they should care about your work. I discuss this more at length in my other blog ‘Manuscript publishing: a beginner’s guide’ in the context of writing a research article. As an author, you must spell out why your research matters to society and how it aims to solve a societal problem. This happens in the introduction.
When writing your manuscript, you can breakdown your introduction into three parts: the background, literature and objective(s). If you’re in the process of writing a scientific manuscript then try to make your introduction account for around 10% of the overall word count. I am going to use the introduction from one of my original research articles as an example, but the approach is not limited to scientific articles. This introduction will be split into the aforementioned three parts so you can see how it has been structured. You can view the whole article here.
In the first paragraph, I attempt to bring readers into the world of my research. I prepare the readers for the specifics by giving a broad introduction in the first two sentences. Then I go into the specifics of my work: metal membranes.
When writing my manuscript, I had considered my main audience to be researchers working in a similar field to me and not necessarily laypeople. This meant I could use technical, but commonly known, abbreviations and terminology. So, I saw it fit to use chemical symbols, chemical formulae, abbreviations, units and technical jargon common to my field.
The findings in this article are from my PhD research. So, I explain to the reader why I spent years of my life researching metal membranes made from a palladium-copper alloy and why they should care. I was fully aware that only researchers in my field would have the most interest in my work so I was able to use technical language. Here’s how my introduction begins:
“Currently, most of the commercially available hydrogen gas is produced via steam methane reforming . However, with the expected growth in the proton exchange membrane fuel cell industry it is anticipated that there will also be a growing need for ultra-pure hydrogen of grade 5.0 (99.999%) [2,3]. Palladium-based dense alloy membranes, such as Pd–Ag and Pd–Cu, are used for hydrogen purification applications due to their high catalytic activity for hydrogen dissociation, high hydrogen permeability and mechanical robustness [4-6]. The Pd–Cu alloy system is of particular interest as the lower Pd content may reduce the cost and the Pd-rich Pd–Cu face centred cubic (FCC) phase exhibits better resistance to H2S poisoning in comparison to other commercially available membranes such as Pd–Ag alloys [7-12].”
Consider your readers when writing your introduction
If I was going to tailor this article to suit a wider audience that might have a passing interest in my work, I would have written it entirely differently. Instead, I would explain that metal membranes made from palladium-copper alloy can be used to purify hydrogen. Why is that useful? Because a special device known as a fuel cell can use the hydrogen gas purified by one of these membranes to make electricity. Then I would explain that making electricity this way is more sustainable and environmentally friendly since you can use renewable hydrogen in a fuel cell that produces no harmful emissions. This can also help to reduce reliance on generating electricity from non-renewable fossil fuels which are commonly attributed to climate change.
So, I’ve highlighted the benefits my work has to society at large. Perhaps your idea can save a substantial amount of money, cut costs, save lives and so on. Mention this as this will help to build an emotional connection with readers so that they can better relate and care even more.
Next, you ought to present to your readers a brief overview of the literature. Describe what other researchers in your field have done and even compare their work with each other. Do they agree? Perhaps not. So, you can offer your opinion as to why. Always aim to cite reliable and trustworthy sources. Rather than reference a website look to use highly-cited articles found in reputable journals or well-known textbooks in your field. Published scientific articles have been scrutinised by other experts in the field during the peer review process. But beware. Not all highly-cited articles contain reliable information. I have witnessed some publications that contain inaccuracies which to the untrained eye can appear reliable. If you’re unsure, always ask a more experienced researcher for their opinion on the veracity of an article.
You’re writing an introduction not a literature review
Even though you should cover some of the research done in your areas both past and present resist the temptation to write a detailed literature review. Remember, that your introduction should account for 10% of the overall manuscript word count. For example, if your manuscript is 5,000 words, then aim to have your introduction be around 500 words. But then consider that your introduction is split into three sections and so your mention of literature in this instance will only be between 150 to 200 words. That only leaves one to two paragraphs where you can briefly discuss the literature. So, only the pick the most relevant, prominent and influential sources.
Choose high-quality and reliable sources
In the next two paragraphs, I present some information from reputable and reliable scientific sources to explain what is so special about my choice of palladium-copper alloy membranes. The explanation is technical since I was writing it for other researchers in my field, but do the same in your respective area. However, do tone the jargon down if you want to appeal to a broader audience.
“According to the Pd–Cu phase diagram, the Pd60Cu40 wt% composition contains a CsCl-type ordered body centred cubic (BCC) phase below 450 °C ; this has been reported [4,7,8,12,14,15] to possess the highest hydrogen permeability within this binary alloy system. Deviation from this optimum composition by 3 wt% or more can result in at least a 50% reduction in hydrogen permeability . Hence, the BCC Pd60Cu40 wt% alloy membranes have been selected for this study and any further reference to Pd–Cu membranes in this work will be of this composition unless otherwise stated.
In the Pd–Cu system, diffusivity of hydrogen in the BCC phase is two orders of magnitude greater than in the FCC phase [14,15,18,19]. At the Pd60Cu40 wt% composition, above 450 °C the disordered FCC phase begins to form and at temperatures higher than 600 °C only this phase exists. The Pd-rich Pd–Cu FCC phase with the composition Pd100−xCux wt% (0≤x≤20) has relatively high hydrogen solubility [20-22] and an enhanced resistance to H2S contamination over the BCC phase [10,12]. Modifying the surface composition of a Pd60Cu40 wt% membrane through the deposition of Pd may introduce a Pd-rich Pd–Cu FCC layer that may potentially improve hydrogen permeability and H2S resistance of the membrane.”
In the last part of your introduction, you need to make clear what the goal is of your work. In the last two paragraphs, I state my aim and how I plan to achieve that aim. The aim was to modify the surface of palladium-copper alloy membranes using a coating technique to see if I can improve their performance. By this point, the reader will know what the problem is I am trying to solve and how I intend to solve it.
What’s the question?
Now, you can present your objectives in a few ways. You could put forth a research question that you intend to answer. For example, ‘can modifying the surface of a palladium-copper alloy membrane enhance its performance for hydrogen separation applications?’
What’s your hypothesis?
Another approach could be to state your hypothesis or hypotheses. So, for my article, I tested the following hypothesis: ‘If the surface of a palladium-copper alloy membrane is modified by depositing a thin-film of pure palladium onto one side it will introduce a larger hydrogen concentration gradient across the membrane and improve overall hydrogen permeability.’
Infinitives are useful too
Finally, you could use infinitives like ‘to examine’, ‘to investigate’, ‘to explore’, etc. An example of this is used in the last part of my introduction:
“The aim of this work is to explore the possibility of creating a Pd-rich Pd–Cu FCC phase on the surface of a BCC Pd60Cu40 wt% membrane that is stable under typical operating conditions to determine the effects on hydrogen permeability. This can be achieved by depositing a Pd thin film onto one side of a Pd60Cu40 wt% membrane using magnetron sputtering. Annealing the surface modified membrane creates a Pd-rich layer containing the FCC phase produced via Cu interdiffusion out of the bulk Pd60Cu40 wt% membrane and into the Pd thin film.
Pure Pd membranes also undergo a phase transformation during thermal cycling in a hydrogen atmosphere which leads to rupturing when the critical temperature of 295 °C is passed at hydrogen pressures below 2 MPa . The Pd–Cu alloy avoids this at the cost of a lower hydrogen surface absorption. Coating the Pd–Cu membranes with a pure Pd surface could lead to enhanced surface absorption of hydrogen whilst retaining the mechanical robustness of the alloy membrane.
Successful manipulation of the Pd60Cu40 wt% alloy surface composition could have the potential to produce a membrane with enhanced properties competitive with the more popular and expensive Pd–Y and Pd–Ag alloy systems.”
Start writing your introduction!
When in doubt, always refer to introductions in other published articles to get a feel for the length, style and approach. Mimic them and take your time as you’re trying to tell a meaningful story.