I. Chemical Composition and Physical Form: From Pure State to Dispersed System
Silicone crude oil (pure silicone oil) is a pure liquid form of linear polysiloxane. Its molecular structure consists of a silicon-oxygen (Si-O) backbone and organic groups (such as methyl and ethyl) side chains. It is colorless, transparent, or pale yellow, odorless, and non-toxic. It has a wide molecular weight distribution, ranging from low viscosity (0.65 centipoise) to high viscosity (million centipoise), all achieved through catalytic polymerization. It exhibits excellent thermal stability (-65°C to 200°C) and chemical inertness.
Silicone emulsions are heterogeneous systems formed by dispersing silicone oil in an aqueous phase through emulsification technology. They are oil-in-water (O/W) emulsions. Its core components are:
Dispersed phase: Silicone oil (20%-30%)
Continuous phase: Deionized water
Emulsifier: Anionic (sodium lauryl sulfate), cationic (cetyltrimethylammonium bromide), or nonionic (polyoxyethylene ether) surfactants
Functional additives: Thickener, preservative, pH adjuster
The silicone oil droplets are refined to micron-sized (1-10μm) using a colloid mill or high-pressure homogenizer, forming a stable emulsion with a milky white or translucent appearance.

II. Application Diversification: From Industrial Lubrication to Daily Chemical Care
Organic silicone oil, thanks to its pure properties, dominates high-end applications:
Industrial Lubrication: Used as high-temperature chain oil and compressor lubricant to meet the demands of extreme operating conditions
Electronic Packaging: Used in LED potting compounds and integrated circuit coatings to provide insulation protection
Pharmaceutical Preparations: Used as ointment bases and sustained-release carriers, leveraging their physiological inertness

Organic silicone emulsions, through water-based transformation, have expanded their application areas:
Textile Finishing: Used as softeners and water-repellents to impart a smooth feel to fabrics (e.g., cationic emulsions used for waterproofing vinylon tarpaulins)
Daily Chemicals: Smoothing agents in shampoos (e.g., amino-containing silicone oil emulsions) and film-forming agents in skincare products
Defoaming Control: In the fermentation industry, 0. Emulsion-based defoamers at a concentration of 0.1%-0.1% can quickly deflate foam.
Architectural waterproofing: Sprayed on concrete surfaces, they form a hydrophobic layer with waterproofing durability exceeding 10 years.

III. Technology Evolution: Composite and Functionalization
Current R&D focuses on breakthroughs in the performance of emulsion systems:
Self-emulsifying technology: Grafting polyether chains (such as silicone-polyether copolymers) onto siloxane segments enables self-dispersion without the need for emulsifiers.
Nanoemulsions: Refining silicone oil droplets to less than 100nm to improve transdermal absorption (in the pharmaceutical field).
Smart responsive emulsions: Developing temperature- and pH-sensitive emulsions for controlled drug release or adaptive lubrication.

The fundamental difference between silicone crude oil and emulsions lies in the trade-off between pure performance and ease of dispersion. With advances in emulsification technology, emulsion systems are approaching the performance limits of crude oil, while crude oil is being modified to develop more specialized functions, creating a mutually complementary and symbiotic industry.