A refreshing review of our new paper on a model of self healing

There are times when one of my less stellar papers, in my opinion, gets accepted for publication without trouble; and, at other times, what I think are very significant papers have lots of trouble.  Perhaps this is a matter of taste, or perhaps papers that are outside the norm are misunderstood and therefore rejected.

As a case in point, I was invited to submit a paper to a special issue of a journal dedicated to self-healing polymers.  The focus of this special issue is on polymers that are made to self heal after mechanical cracking by incorporating tiny reserves of monomer that runs into cracks as they form, thus filling them and repairing the material.

Our work is very different, so I thought that our invitation was an effort by the editors to broaden the scope of the journal.  However, we were shocked to find that our paper was rejected without review based on the assessment that the work was "incremental."  We responded to the editors, reminding them that we were invited to write the paper.  The next email informed us that the editors had made an error,and that the paper would go out for review.

Two reviewers responded and one of them recommended that our paper be rejected on the grounds that the work was incremental.  However, the editor gave us the opportunity to respond.

In the meantime, we had found data at the extremes that were inconsistent with our model.  We fixed the model with one simple change in the underlying assumptions, and the new model fit all of our data. (This in itself is a very interesting story which I will report on later.) We revised the manuscript to include the new data and resubmitted it.

The editors sought an opinion from a forth reviewer.  An excerpt from his/her comments, follow,"One of the reviewers evidently commented that this work is incremental. However, I don’t agree. The authors are clearly refining their model, and this is an entirely new set of data and observations. The authors search for a better physical understanding will naturally require a significant amount of investigation, and it is helpful to the community to see the work as it unfolds, not wait 25 years for a definitive explain‐all paper that may never appear."

We, of course, agree with this reviewer, and are glad that this paper came to a happy ending, especially in light of the fact that I believe that our new results provide important insights that are taking us a step closer to understanding a new phenomena. 

The new version was accepted with minor revisions suggested, which we made.  The paper was then accepted and the page proofs arrived a couple weeks ago.  We fixed minor typos and now the paper is in the queue for publication in the early summer.  I ust learned today that the electronic version is already available online.  It's ironic that we were even invited to provide an artistic rendition of a figure that might be used as a cover photo.  What a difference a revision makes!  From incremental to cover story material with the change of one variable!

For the interested reader, below is the introductory paragraph, which describes our work and how it differs from the norm, "Structural damage and degradation of a polymer is usually associated with cracking. Mitigating damage or developing methods to promote healing in polymeric materials after cracking is an active area of research motivated by its practical utility. White and coworkers reported on a structural polymeric material with the ability to autonomically self-repair cracks. Such polymers incorporate a microencapsulated healing agent that is released in the cracking process with polymerization being triggered by contact of a catalyst with the healing agent, thus bonding the crack faces. White observed as much as 75% recovery in toughness. 

"Our work presented here is different in two regards. First, the sample is a dye-doped polymer rather than a neat polymer and the degradation process is through optically induced burning, so chemical changes are induced rather than solely mechanical/structural damage – though cracking can accompany burning. The dopant molecules thus mediate the phenomena. The degree of damage is observed using optical techniques, the simplest of which is the detection of a color change. Secondly, the healing process is a microscopic one, originating at a molecular level that we believe involves a cooperative process of aggregates of molecules. The polymers of interest to our work have applications as optical materials where photodegradation is a common cause of optical and optoelectronic device failures, either as catastrophic failure or a slow deterioration of performance."

The final paragraph in the conclusion succinctly states what we believe is cool about our work, as follows, "The concept that a material would exhibit such complex behavior without intentional design by the experimenter is an interesting one. Though self-healing is a process with great practical utility, it is intriguing that nature has been kind enough to provide an inherently smart material system that appears to behave in a way contrary to most others; it mediates recovery in a world in which irreversible damage is the norm. Further advances in understanding the physics underlying this phenomena will surely enable new applications that require materials to withstand high light intensities; and, may lead to new physics.

Now the next battle...