In the field

TDA Logic in the field

A list of public formulation discussions in which TDA Logic reasoning was applied, with links to the original threads and to the lab’s case-study analyses.

Published 6 November 2026 · Primary reference: Pensive Beauty® Nanoscience Labs (2026), Zenodo

What is listed here?

The threads below are on the Chemists Corner forum, Cosmetic Science Talk. In each, a formulator raised a problem in public and TDA Logic reasoning, chiefly questions of charge, ionic strength, ingredient location and pH, was applied in reply. Replies posted by the TDA_Logic account are the lab’s own contributions. Other participants’ posts are their own; they are not quoted or summarised as views here, and listing a thread does not imply that anyone else in it endorses TDA Logic.

Thread titles below are descriptive titles written for this page, and each links to the original discussion. The summaries describe the topic of each thread rather than any participant’s position. Where the lab later wrote a fuller analysis, a link to the matching case study follows the summary; those case studies are paper analyses of conventional formulas, not bench results.

Threads analysed as case studies

• Calcium bridging: a preservative blend that curdled an anionic cream

  Calcium in a preservative blend bridged an anionic emulsifier and curdled a facial cream at 40 °C. Lab analysis: case study 1.

• Electrolytes and a lamellar cream that separated after small changes

  Humectant salts, a chelator and an oil swap loosened a lamellar cream until it separated. Lab analysis: case study 2.

• A carrier that holds the preservative: cyclodextrin in a water-based serum

  A cyclodextrin carrier and the finished pH set how much preservative is free to act in a serum. Lab analysis: case study 3.

• Charge state decides it: a quaternary ammonium meets carbomer

  A quaternary ammonium clumped with neutralised carbomer; at low pH the two coexist. Lab analysis: case study 4.

• Urea pH drift: an unbuffered system and a slowly hydrolysing ingredient

  An unbuffered urea formula rose 1.65 pH units in a week; hydrolysis, buffering and contamination explain it. Lab analysis: case study 5.

• Micelle or droplet: why a shampoo’s fragrance did not stay on hair

  A shampoo fragrance held in micelles rinsed away, while droplets are captured on hair. Lab analysis: case study 6.

• Cationic and anionic in the same cream: a curl-defining hair product

  An anionic emulsifying wax met a cationic surfactant, and anionic gums met a cationic polymer. Lab analysis: case study 7.

Other discussions

• Choosing a chelator for a high-ethanol solution

  Why EDTA salts do not dissolve at high ethanol levels, and the free-acid chelators considered instead.

• Dissolving salicylic acid powder in a cleanser

  How the formula pH sets the free-acid fraction of salicylic acid (pKa about 3.0), and what that means for dissolving it.

• A cream that changed colour on storage

  Oxidation of a rosemary-derived antioxidant to coloured products, and the roles of trace metals and headspace oxygen.

• What gives skincare a silky finish

  How emollient spreading behaviour, elastomers, powders and droplet size shape skin feel.

• Separation in an anhydrous wax stick

  Oil weeping from a wax stick, discussed in terms of wax and oil polarity and the crystal forms of shea butter.

• Phase separation in a water-in-oil cream

  A discussion of why a water-in-oil cream separated and what to change.

• Reviewing a leave-in hair formula

  A request for a compatibility review of a leave-in hair product before making it.

• Formulating a body spray

  A discussion of how to formulate a fragranced body spray.

• Dispersing essential oil in a water-based mist

  Why solubilising oil in micelles takes several parts of solubiliser per part of oil, the tack that follows, and finer droplet dispersion as an alternative.

How can I discuss or question TDA Logic?

Readers are welcome to discuss, test and challenge TDA Logic in public forums, where other formulators can examine the reasoning. When doing so, please cite the primary reference: Pensive Beauty® Nanoscience Labs (2026). TDA Logic: The Tri-Domain Placement Logic Succeeding 1940s HLB Logic in Nanoscale Cosmetic Formulation (Version 1.0) [Preprint]. Zenodo. https://doi.org/10.5281/zenodo.23384911. See how to cite.