Polyion Complex Film Stability via Nonionic Surfactant Mediator

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Solution Overview

Problem

Existing methods for preparing polyion complex films, such as those using spin coating or spraying, face challenges in stability and control, particularly in forming thick films on keratin substrates like skin, and are prone to instability issues with polyion complex particle dispersions.

Innovation Solution

A composition comprising polyion complex particles with a cationic polymer, an anionic polymer, and a hydrophilic or water-soluble UV filter, along with a physiologically acceptable volatile medium, is developed to create a stable dispersion that can be easily applied to keratin substrates and dried to form a thick, water-resistant film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polyion complex particles are used to simplify film preparation, then ease of manufacture is improved, but dispersion stability deteriorates causing particle precipitation

Engineering Contradiction:

Improvefilm preparationVSAvoiddispersion stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

A nonionic surfactant is introduced as an intermediary substance to stabilize the polyion complex particle dispersion. The surfactant adsorbs at the particle interface, preventing aggregation and precipitation while maintaining ease of film preparation through simple spraying or brushing methods.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The formulation creates a composite system combining polyion complex particles, nonionic surfactant, and volatile medium. This composite approach leverages the stabilizing effect of the surfactant to maintain dispersion stability while preserving the ease of manufacture provided by the particle form.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If spin coating process is used to prepare polyion complex film, then film quality is improved, but device complexity and operation difficulty increase due to high speed rotation requirement

Engineering Contradiction:

Improvefilm qualityVSAvoidoperation difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The complex high-speed rotation mechanical system of spin coating is replaced with a simple spraying or brushing application method. The polyion complex particles in dispersion form a uniform film through capillary action and evaporation, eliminating the need for complex rotational mechanics while maintaining acceptable film quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If spraying process is used to prepare film in-situ on keratin substrate, then ease of operation is improved, but manufacturing precision deteriorates making it difficult to control film thickness

Engineering Contradiction:

Improveease of applicationVSAvoidfilm thickness control

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The formulation parameters are optimized to enable thick film formation through spraying. By adjusting the polyion complex concentration, surfactant content, and volatile medium composition, the dispersion achieves appropriate viscosity and flow characteristics that allow controlled thick film deposition through simple spraying without requiring precise thickness control during application.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides a stable and easily preparable polyion complex film with cosmetic functions like UV filtering, odor absorption, and skin protection, which is resistant to water but can be easily removed under alkaline conditions, ensuring long-lasting and safe application.

Implementation Method 1

A polyion complex which is formed with an anionic polymer and a cationic polymer has already been known

Methodology Applied

Scientific EffectElectrostatic interaction: Electrostatics

Implementation Method 2

drying the composition to form a cosmetic film on the keratin substrate

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS11642297B2Combination of polyion complex particle and hydrophilic or water-soluble UV filter

Publication Date: 2023.05.09 LOREAL SA

AI summary

The present invention relates to a composition according to the present invention comprises: (a) at least one particle comprising at least one cationic polymer, at least one anionic polymer, and at least one hydrophilic or water-soluble UV filter; and (b) at least one physiologically acceptable volatile medium. The composition according to the present invention is stable, and can have a variety of cosmetic functions. For example, the composition according to the present invention can prepare a film which can have cosmetic effects such as UV filtering, as well as absorbing or adsorbing malodor, changing the appearance of a keratin substrate such as skin, changing the feel to the touch of the keratin substrate, and/or protecting the keratin substrate from, for example, dirt or pollutants.