Through the use of the statistical concept of allocation entropy and by combining theoretical elements derived from statistical thermodynamics and information theory, a Markovian expression of the absolute entropy of a gaseous mixture is achieved. In the formula, the quality of the gas is represented by the entropy of a Markov source describing the mixture in terms of concentrations of single types of particles involved. The special structure of this formula opens the way for the construction of a theoretical model for the study of codified aggregative phenomena. The concepts of “ideal elementary particle” and “ideal aggregate” are firstly defined and then a particular reaction is proposed as a hypothetical aggregative process. Then, relations that describe the thermodynamics of the formation process of even very complex structures are obtained as a consequence of the combination rules. These are expressed in terms of “coding factor”, a kind of necessity rate on a random basis. In fact, thanks to the use of the Markovian expression of absolute entropy, the elaborated model allows the use of more or less stringent aggregation codes so as to simulate environments totally dominated by chance or totally deterministic, passing with continuity through all possible intermediate situations. Finally, the structure of the model permits to distinguish between processes that develop as a consequence of aggregative inclinations implicit in the system itself (autopoietic processes) and processes that develop as a consequence of the ordering action of entities outside the system (heteropoietic processes).
By adding possible temporal changes of form and/or functionality to additive manufacturing, 4D printing brings new potentials to this still expanding new field. While there is transgressive promise associated with this technology with high growth potential in academic research, targeted applications are far from being achieved. On the basis of this assessment, it appears that related fields, in a situation of possible disciplinary porosity, can, with some creativity, move away from the current highly self-centered work to try to re-invigorate 4D printing, provided that the risk-taking in interdisciplinary research is better supported. A proposal for a "roadmap" that is likely to be improved is proposed: it concerns on the one hand, a scientific axis where the 4D activity researched relies on original couplings between materials (including meta-materials) and processes, hybrid multi-material fabrications, and on the other hand, an organizational axis where interdisciplinarity and risk-taking would be privileged.