Introduction

In liquid filtration, the surface properties of membrane materials play a major role in determining filtration behavior, especially in applications requiring high throughput and consistent wetting. Many raw membrane materials, such as PTFE or PP, are naturally hydrophobic and require hydrophilization treatment to make them compatible with aqueous solutions. This article explains how hydrophilization works and why it is essential for modern filtration processes.

1. What Is Hydrophilization Treatment?

Hydrophilization is a surface modification process that increases the affinity of membrane materials toward water. By improving wettability, hydrophilic treatment allows water or solutions to enter and pass through the membrane more efficiently.

• Transforms hydrophobic surfaces into water-friendly ones
• Reduces the need for pre-wetting procedures
• Improves consistency in filtration start-up and flow rate

2. Why Hydrophilization Is Important

Hydrophilic membranes provide several advantages in liquid filtration:

• Faster Wet-Out: Membrane fully wets immediately, avoiding air entrapment.
• Stable Initial Flow: Prevents pressure spikes caused by slow wetting.
• Higher Filtration Efficiency: Liquid uniformly spreads across membrane surface.
• Improved Retention: More consistent pore accessibility improves accuracy.
• Better Compatibility: Suitable for aqueous biological liquids, buffers and media.

3. Hydrophilization Methods

Common industrial hydrophilic modification techniques include:

• Plasma Treatment: Introduces oxygen-containing functional groups to increase surface energy.
• Surface Grafting: Polymer chains with hydrophilic properties are bonded to membrane surfaces.
• Chemical Oxidation: Acts on hydrophobic polymers to generate hydrophilic functional groups.
• Blended Hydrophilic Additives: Hydrophilic materials are embedded within the polymer matrix during membrane casting.

4. Which Membrane Materials Need Hydrophilization?

Not all filter membranes are naturally hydrophilic. The following commonly require modification:

• PTFE (Hydrophobic): Requires strong hydrophilization for aqueous filtration.
• PP: Often modified when used for aqueous depth filtration.
• PES & PVDF: Usually produced as hydrophilic, though hydrophobic versions exist.
• Nylon: Naturally hydrophilic but can be further enhanced for specialty applications.

5. Applications of Hydrophilic Membranes

Hydrophilized membranes are widely used across industries:

• Biopharmaceuticals: Buffer filtration, sterile filtration, vaccine production.
• Food & Beverage: Clarification of liquids, sterile cold filtration.
• Chemical Processing: Water-based reaction media and analytical sample prep.
• Laboratory: Aqueous sample preparation and microfiltration.

6. Hydrophilization and Filter Performance

Hydrophilization directly improves performance indicators:

Hydrophilization Benefit

Performance Factor
Wettability	Immediate wetting, stable-up pressure
Flow Rate	Reduced resistance and improved throughput
Consistency	Uniform pore activation across membranetd>
Retention	Enhanced accuracy due to improved pore accessibility

Conclusion

Hydrophilization treatment is essential for converting hydrophobic membrane materials into reliable and efficient liquid filtration media. By improving wettability, flow performance and consistency, hydrophilic membranes provide significant advantages across pharmaceutical, food, chemical and laboratory applications.

Purchase Suggestion

We provide a full range of hydrophilic membrane filters, including PES, PVDF, Nylon, hydrophilized PTFE and modified PP. Contact our technical team to select the best membrane for your liquid filtration process.