Makeup trends changed drastically during the past year. With the addition of a work-from-home option throughout the world, many consumers realized that wearing a full face of makeup every day for work was a waste of time, money and effort. Consumers leaned toward purchasing a single cosmetic product that can serve as various parts of a makeup, hair care or skin care routine. A great example is Glossier Cloud Paint described on Glossier’s website as a “seamless, buildable gel-cream blush.”¹ Consumers noticed it is also a great alternative for a sheer eyeshadow, lip tint and cream blush all wrapped into one. Products like this enable the consumer to save time and money.

Another trend during the past year was the “no makeup, makeup” look. Full coverage foundations were replaced with tinted sunscreens, BB creams or just a touch of concealer. Cream products such as blushes, highlighters and bronzers replaced powders to create a more natural look. Some finishing touches of brow pencil and mascara create a natural makeup look ready for hours of Zoom meetings. These fast-evolving consumer trends and the industry’s responses to them highlight the need for continuous innovation to meet ever-changing consumer demands.


Limited PalletTEs?

Cosmetic companies often get stuck in a rut of formulating products utilizing only small variations in ingredients or merely trying new combination of ingredients. As consumer requirements become more demanding and the market grows more competitive, companies research new and nontraditional ways of formulating to benefit users by creating products that feel personalized to them and provide new sensory and functional benefits. Glossier is part of the makeup revolution shaped by Millennials and Gen-Z consumers who are attracted to its clean beauty initiatives and personalized services.² Glossier and other indie brands focus solely on specific consumer needs due to their small size. In contrast, larger cosmetics companies focus on national and international markets. With the consumer’s help, smaller brands begin to flourish and are acquired by larger corporations. Take, for example, Shiseido; the multinational purchased Drunk Elephant, a smaller indie brand. Acquisitions give indie brands access to resources and funding to help grow their businesses.


Why Smart Materials?

As these companies receive more funding and investors, they can use that money to research and develop new products using materials that are not as common in the cosmetics industry. At the same time, larger companies must become more innovative to remain more competitive. This requires exploring and incorporating new classes of materials into formulations which bring about differentiated consumer perceivable differences. Smart materials are a class of materials that can potentially bring this differentiation and allow a generation of new range of cosmetic products. Smart materials are a class of materials that undergo physical or chemical change based on an external stimulus. This stimulus includes changes in temperature, humidity and pH; just to name a few. There could also be light or ultrasound-based triggers.

Smart materials are already used in the automotive, the sporting goods and clothing industries. Smart materials reduce noise in vehicles and vibrations in golf clubs. Nike’s Dri Fit fibers wick sweat from clothing. Cosmetics companies are interested in smart materials’ ability to completely change a product based on the environment in which the product is used. Larger cosmetic companies are exploring smart materials in formulations and as a result starting to explore smart formulation-based products to keep up with emerging innovations. These materials hold significant promise for wider scale application in the cosmetic industry. They bring about personalization and differentiation, device product combination and more.


Product Differentiation

Consumers are more selective when choosing new cosmetic products. They want products that can adapt to whatever look they are going for at the time of application—not just a boring product that does basic things. Smart formulations can potentially differentiate from normal products due to the inclusion of various smart materials. One type of smart materials which is starting to be explored in the cosmetic industry is shape memory polymers (SMPs). SMPs can be deformed and returned to their original shape through external stimulus. Their semi-crystalline state differs from regular polymers which only exist in fully crystalline or fully amorphous state. This semi-crystalline behavior allows the SMP to hold its deformed shape and, over time, go back to its original shape. SMPs have two different “transition temperatures.” These are the temperatures at which the state of the polymer goes from a crystalline state to an amorphous state or vice versa. When starting out, the initial shape is in a fully crystalline/rigid state. When heated to a specific temperature, the polymers loosen up to a more amorphous/shapeless state. When the formulation reaches the second transition temperature, the state of the polymer goes from fully amorphous to fully crystalline. These polymers could be used to bring about more drastic effects in shape changes, such as eyelash curvature or hair shape changes. Examples of these changes are detailed later in this article.


Personalization/Device Combination

The biggest appeal to using smart materials in cosmetics is their ability to change based on an external stimulus. These stimuli can be either environmentally or manually provided in order to change the way the product works. Formulations incorporating smart materials can even be made based on specific regions of the world, allowing some products to react differently to more humid or colder temperatures than others through having built-in temperature or humidity responsiveness. Creating products that are able to adapt better based on the specific environment allows the consumer to feel as if the product was made specifically for them.

Another way to change a product is by the consumer manually adding an external stimulus. The most common way for this to be done is through using a smart product in combination with a device that will act as the stimulus. Light therapy for acne is a practice that is being used more and more nowadays due to an increase in acne around the chin and cheek area from consumers wearing masks. Light therapy “emits two kinds of LED light: red and blue. Blue light kills acne-causing bacteria, and red light reduces inflammation.”³ This is a great device that could be used in conjunction with a smart formulated product to release an anti-acne active triggered by light. Efficacy may be enhanced via the combination of light therapy and smart formulation. 

Ultrasonic face brushes can be used in conjunction with a smart product, too. These brushes use vibration and ultrasonic waves to remove dirt and debris from skin while reducing the appearance of pores. When used in conjunction with an ultrasound activated smart formulation, a skin benefit agent, such as peptides, could be released by specific frequency in the device. Figure 1 highlights a schematic of a smart hydrogel that is activated by light and/or ultrasound to undergo swelling and release an active. Using these products, along with a device, is more effective than using the product alone. It is a great business model for companies and will open new revenue streams.

The addition of smart materials in cosmetics benefits the consumer and the companies that use them. Companies can venture into new business opportunities such as creating devices that will work best when paired with one of their products. Researchers have started to try and understand the capability of smart materials and all of their possible uses. These uses and examples are discussed further in the following sections.


Smart Materials Applications

Smart materials can be used in formulations such as mascara. Oil-in-water emulsion mascara formulated with methoxy poly(ethylene glycol)-b-poly(D,L-lactide) (mPEG-PLA) has shown successful thermoresponsive behavior in making a longer-lasting lift and curl on false eyelashes using a heated mascara wand (Chen et al.).⁴ The heated mascara wand temperature is maintained at 65°C. There is a directly proportional relationship between the concentration of the thermoresponsive shape memory polymer, mPEG-PLA, and the viscosity of the mascara formulation. Remember, a less viscous mascara formulation is easier to apply for the consumer, but it is an increase in viscosity that will contribute to the enhanced curl and lift of the lash. The heated mascara wand contributes to a higher temperature at application with a lower viscosity and once removed the cooling process increases the elasticity for a more curled shape (Figure 2).


Skin Care

Skin care formulations using nanoemulsions are gaining in popularity throughout the beauty industry. Their smaller droplet size pentrates deeper into the skin, which is essential for effective transdermal delivery of active ingredients such as anti-aging, moisturizing, sun damage prevention and whitening.⁵ Adding a stimuli responsive aspect to nanoemulsions can enhance both functional and sensorial efficacy of these types of applications. In this regard there has been very recent work on designing thermoresponsive nanoemulsions.⁶

The skin regeneration benefits delivered via skin peptides is a growing area of research, too. Epidermal growth factors specifically prompt collagen, elastin and extracellular matrix biosynthesis. Eskens et al⁷ designed a smart hydrogel system for epidermal growth factor formulation and stability.

Hydrogels are optimal for topical hydration. In this hydrogel design, thermal and shear-induced gel degradation were used for an even application across the skin and for potentially bringing about a sensorial differentiation. Sodium alginate is a natural polysaccharide derived from brown alga commonly used in the consumer industry for its high stability, thickening properties and solidification.⁸ It, too, was used in this study to support the efficiency of the epidermal growth factor as it has healing properties. Another component, methylcellulose, has thermoresponsive properties where gelation occurs at increased temperatures.

Combining methylcellulose and sodium alginate builds a supportive preservation system as a fluid gel for the epidermal growth factor active ingredients due to their gelling and immunogenic capabilities. Once combined, these polymers enhance the thermoresponsive behavior of the formulation. Methylcellulose has a hydrophobic gelling mechanism that increases with concentration while the alginate heightens the thermal responsiveness.

Hair Care
Another popular area where smart materials are used is in hair care. Smart formulations can be used to form a barrier around hair follicles, protecting them from heat damage. The barrier also locks hair styles in place throughout harsh environmental conditions. There has been research on smart responsive coatings for hair care.⁹ It is expected that with the differentiated performance benefits, these types of smart material coatings will continue to be explored for various hair care applications.

Thermoresponsive smart polymers are often the first choice when it comes to hair care. Chitosan is a natural cationic copolymer ideal for building hydrogel structures that have temperature sensitive properties. At elevated temperatures the structures have a gel-like formation.

Hydrogel structures like these can potentially be adopted into the cosmetic industry for heat-activated beauty care products which are used in conjunction with heated hair and eyelash tools. As consumers style their hair, the chitosan-infused product helps hold the desired shape for a longer amount of time due to its gelling properties. Chitosan and methylcellulose are two thermoresponsive polymers that, when combined with a chelating agent such as acetic acid, create a thermoresponsive hair gel that is able to hold a hairstyle for hours on end with little to no drag due to gravity (M.Hartson, C.Coyle S.Amin et al.).¹⁰ Chitosan is an affordable renewable biopolymer which goes hand-in-hand with Millennial and Gen-Z interest in clean beauty. The same marketing interest applies to methylcellulose due to its biodegradability.


The Future

These examples illustrate the potential of smart materials. They can play a significant role in bringing about differentiation and enhancing personalization in cosmetics. Although smart materials have been widely adopted in other industries including automotive, military, fashion and medicine, they haven’t been widely adopted in the cosmetic industry. With increased need for faster paced, differentiated innovation, smart materials have a role to play in makeup, hair care and skin care formulations. The ability for a material to change based on the surrounding conditions is impressive, and we’re only just getting started on uncovering different ways to formulate with them.  

References

1. Cream Blush: Cloud paint. Glossier. (n.d.). www.glossier.com/products/cloud-paint
2. Columbia Business School – the Eugene Lang Entrepreneurship Center. “The Quiet, Quick Rise Of Indie Beauty Brands.” Forbes, Forbes Magazine, 26 Mar. 2021, www.forbes.com/sites/columbiabusinessschool/2021/03/04/the-quiet-quick-rise-of-indie-beauty-brands/?sh=3901234732c1
3. Krieger, L. (2017, October 12). Adventures in technology: A working mom test-drives the new neutrogena light therapy acne spot treatment. Content Lab U.S. www.jnj.com/innovation/working-mom-test-drives-the-new-neutrogena-light-therapy-acne-spot-treatment
4. Chen S. and Amin S. Design of high-performance curling mascara through utilization of smart thermoresponsive polymer. International Journal of Cosmetic Science (2020).
5. Sonneville-Auburn, Odile. “Application of Nanoemulsions in Cosmetics.” Nanoemulsions, Academic Press, 2 Mar. 2018, www.sciencedirect.com/science/article/pii/B978012811838200014X.
6. Thermoresponsive Oil-in-water Nanoemulsion, WO 2020/112595 A1
7. Eskens, O.; Villani, G.; Amin, S. Rheological Investigation of Thermoresponsive Alginate-Methylcellulose Gels for Epidermal Growth Factor Formulation. Cosmetics 2021, 8, 3.
8. Zheng, Jiong, et al. “Effects of Sodium Carboxymethyl Cellulose on Rheological Properties and Gelation Behaviors of Sodium Alginate Induced by Calcium Ions.” LWT, vol. 103, Apr. 2019, pp. 131–138. EBSCOhost, doi:10.1016/j.lwt.2018.12.081.
9. Responsive Coatings for Hair Fibers, WO 2020/077282 A1
10. M. Hartson, C.Coyle, S.Amin. Publication in preparation (2021).

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About the Authors
Meghan Hartson is a senior at Manhattan College majoring in chemical engineering with a cosmetic engineering concentration as well as a minor in chemistry. This past year, Hartson worked in the cosmetic research lab at Manhattan College where she studied smart materials and learned how to formulate hair gels using them. She has worked in the industry for two years, first interning last year at Teawolf, a food and beverage manufacturing plant owned by Döehler, and, most recently, interning for Nalco Water, an Ecolab Company, as a technical sales representative intern.

Ciara Coyle is a student at Manhattan College pursuing her bachelor’s in chemical engineering with a concentration in cosmetics and minor in chemistry. She is on track to graduate in May 2022. Coyle is also an undergraduate research student in the cosmetic lab at Manhattan College as well as the founder of the Cosmetic Engineering and Chemist Society. Her most recent industry role was as a hair care research and development intern for Aveda at the Estée Lauder Companies. She has also interned at the Arizona Beverage Company and Mutch Associates.

Samiul Amin is currently associate professor of chemical engineering at Manhattan College. He leads the cosmetic engineering focus area. Prior to joining academia in March 2018, Prof. Amin was in industry for 20 years, working across engineering, R&D and innovation management in global multinationals such as ExxonMobil, Unilever, L’Oréal and Malvern Instruments in Asia, Europe and the US. His area of expertise is formulation design, smart formulation design through automation, sustainable cosmetic formulations and advanced characterization.