Synthesis of Plant Phenol-derived Polymeric Dyes for Direct or Mordant-based Hair Dyeing

The overall goal of this experiment is to confirm whether pre-synthesized polymeric dyes derived from plant phenols can dye human keratin hairs within an acceptable time frame, compared to commercial hair dyes. This method describes the synthesis of the Nobel human hair dye. The main advantages of this dyeing technique are that it uses eco-friendly materials, it can give rise to various colors and displace resistant detergents.

Our method shows that polymeric dyes derived from plant phenol polymerization can directly attach to keratin hair surfaces, in addition, the colors and shades are easily variable with metallic salts and pH-adjusting agents. The most important step in this method is to polymerize the natural phenols with oxidants such as Lachesis for further dyeing processes. Increased binding ability with polymerization allows natural phenol variants to directly bind into keratin surfaces.

To begin dye preparation, first weigh 0.1 grams of catechol and 0.1 grams of catechin hydrate and add them to 32 milliliters of 100 millimolar sodium-acetate buffer. Add eight milliliters of absolute ethanol and swirl the solution to dissolve the dye. Weigh 10 milligrams of Tremetes Versicolor Laccase and add it to the buffer solution.

Mix vigorously and then pour the solution into a square Petri dish. Incubate the dish on a shaking incubator at room temperature for 24 hours. Dramatic color change of the solution from clear to dark black will be observed.

Pour the solution into a 50 milliliter tube and centrifuge it for 10 minutes at 20, 000 times G to spin down insoluble particles. Transfer the deep black supernatant to an ultrafiltration cell. Desalt the reaction solution using a five kilo Dalton ultrafiltration disc with nitrogen pressure.

The reaction volume should now be concentrated to around 20 milliliters. Add 150 milliliters of distilled water to the 20 milliliter reaction buffer. Filter the diluted buffer solution with the ultrafiltration disc until the volume is concentrated to 25 milliliters.

Repeat this concentration process a further two times. The plant phenol derived polymeric dye can now be prepared for use under eight different component mix conditions on test hair. To prepare a simple dye solution, first mix five milliliters of distilled water with one milliliter of the concentrated, desalted polymeric dye.

Next, prepare a mordent solution by combining one milliliter of the concentrated desalted polymeric dye, five milliliters of distilled water, and 0.33 grams of iron sulfate. Vortex the mixture vigorously to dissolve the iron sulfate powder. Make an acidic dye solution by measuring five milliliters of distilled water and then adjusting the pH to three, using hydrochloric acid.

Add one milliliter of desalted polymeric dye solution and 0.33 grams of iron sulfate. Then, prepare an alkaline dye solution by adjusting the pH of five milliliters of distilled water to 11 using sodium hydroxide. Add one milliliter of the polymeric dye stock, and 0.33 grams of iron sulfate.

To make an acidic acid-treated solution measure one milliliter of glacial acidic accid and add it to five milliliters of distilled water before adding dye stock and iron sulfate. Next, mix the ammonia treatment solution by adding one milliliter of ammonia water to five milliliters of distilled water. Add in one milliliter of dye stock and 0.33 milligrams of iron sulfate.

For the plant monomers, weigh 0.1 grams of catechol and 0.1 grams of catechin hydrate and add these to six milliliters of distilled water along with iron sulfate. Once the six test dye solutions are prepared, immediately add a 0.2 gram tress of five centimeter long gray human hair to each tube. Incubate the tresses at 32 degrees Celsius in a shaking incubator for 2.5 hours.

Remove the hair tresses from the dye tubes and rinse them with tap water. Dry the tresses using an electronic hair dryer. Color change will be noticeable to the naked eye.

To quantify the color change after dyeing, crumple the hair tress into a ball and place it under the lens of a colorimeter. Measure the color parameters of the dried tress and then reposition the hair and repeat the readings on a different section. Measure the color parameters of each dyed tress seven times.

Calculate the averages and standard deviation of each parameter to obtain a color profile for each dye condition. To test color durability, dissolve 200 milligrams of sodium dodecyl sulfate detergent, or STS in 40 milliliters of distilled water. Add a died hair tress to the STS solution and leave it to incubate at room temperature for five minutes.

Remove the hair and then rinse it with enough running water to remove the detergent. Dry the tress with an electronic hair dryer to remove the moisture. Use the colorimeter to measure the color parameters of the hair once more.

Next, dissolve 800 milligrams of STS in 40 milliliters of distilled water to make a more concentrated detergent solution. Soak the same tress once more for five minutes at room temperature and then dry and repeat the measurement of color parameters. Repeat this strong detergent wash a further two times on the same tress to assess color durability.

Measuring the color parameters between every soak. This graph shows the delta E values of human hair tresses under different dyeing conditions. Polymeric dyes induced a significant change in hair color from the base keratin.

This was not observed with the plant monomers only where the innate gray color remained. Whilst delta E was similar, coloration was also visibly changed by the addition of the Mordanting agent. To check whether Mordanting agents induce coloration with plant phenolic monomers, iron ions were added to the monomers without oxidative polymerization.

This proved effective at dyeing hairs from gray to deep black. The effective pH on dyeing using iron ion polymeric dye complexes was evaluated. Whilst the pH three or pH 11 conditions had little impact on delta E, the resulting color was notably different.

Hair color also varied depending on which pH adjusting agent was used. Despite similar delta E values, color parameters of the hair under different conditions were relatively disparate, consistent with the observed diversity. Detergent resistance tests showed all conditions generally maintained delta E values against STS treatments.

This indicated the use of polymeric dyes with or without Moredanting resulted in permanent dyeing. Plant monomer dye without polymerization resulted in less stable coloration. After watching this video, you should have a good understand over how to use eco-friendly, natural, aromatic polymer-mimetics for human hair dyeing.

Many researchers have tried to develop safe and eco-friendly dyeing agent, however, most products just employ natural plant extracts that cannot act as dyeing agent. After its development, this technique paved the way for researchers in the field of hair dyeing, we believe that natural aromatic polymers such as ricotin, melanin and the poli-flavonoid can replace conventional dyeing systems which contain allogenic and carcinogenic compounds. Although this might clearly indicate that natural aromatic polymer-mimetics act as active agents for human hair dyeing, a strict toxicity test must be required before human use.

Currently, we are using similar methodologies to vacate employing eumelanin-like aromatic polymers, analogous to the existing pigments in human hair, for use in hair dyes.