Surface properties of poly(imide-CO-siloxane) block copolymers
Authors: Novák Igor 
Published: November 2013

Surface Properties Of Poly(Imide-Co-Siloxane) Block Copolymers Aigor Novák, A,Banton Popelka, Cpetr Sysel, A,D Igor Krupa, Aivan Chodák, Amarian Valentin, Ajozef Prachár, Evladimír Vanko Apolymer Institute, Slovak Academy Of Sciences, Bratislava, Slovakia Bcenter For Advanced Materials, Quatar University, Doha, Quatar Cdepartment Of Polymers, Institute Of Chemical Technology, Faculty Of Chemical Technology, Prague, Czech Republic Dcenter For Advanced Materials, Qapco Polymer Chair, Quatar University, Doha, Quatar Evipo, Prtizánske, Slovakia Abstract Polyimides Present An Important Class Of Polymers, Necessary In Microelectronics, Printed Circuits Construction, And Aerospace Investigation, Mainly Because Their High Thermal Stability And Good Dielectric Properties. In The Last Years, Several Sorts Of Block Polyimide Based Copolymers, Namely Poly(Imide-Co-Siloxane) (Pis) Block Copolymers Containing Siloxane Blocks In Their Polymer Backbone Have Been Investigated. In Comparison With Pure Polyimides The Pis Block Copolymers Possess Some Improvements, E.G. Enhanced Solubility, Low Moisture Sorption, And Their Surface Reaches The Higher Degree Of Hydrophobicity Already At Low Content Of Polysiloxane In Pis Copolymer. This Kind Of The Block Copolymers Are Used As High-Performance Adhesives And Coatings. The Surface As Well As Adhesive Properties Of Pis Block Copolymers Depends On The Content And Length Of Siloxane Blocks. The Surface Properties Of Pis Block Copolymers Are Strongly Influenced By Enrichment Of The Surface With Siloxane Segments. Micro Phase Separation Of Pis Block Copolymers Occurs Due To The Dissimilarity Between The Chemical Structures Of Siloxane, And Imide Blocks Even At Relatively Low Lengths Of The Blocks. The Surface Energy Of Pis Block Copolymer Decreases Significantly With The Concentration Of Siloxane From 46.0 Mj.M-2 (Pure Polyimide) To 34.2 Mj.M-2 (10 Wt.% Of Siloxane), And To 30.2 Mj.M-2 (30 Wt.% Of Siloxane). The Polar Component Of The Surface Energy Reached The Value 22.4 Mj.M-2 (Pure Polyimide), Which Decreases With Content Of Siloxane In Pis Copolymer To 4.6 Mj.M-2 (10 Wt.% Of Siloxane) And 0.8 Mj.M-2 (30 Wt.% Of Siloxane) The Decline Of The Surface Energy, And Its Polar Component Of Pis Block Copolymer With Raising Siloxane Content Are Very Intense Mainly Between 0 And 10 Wt.% Of Siloxane In Copolymer. In The Case Of Further Increase Of Siloxane Concentration (Above 20 Wt.% Of Siloxane), The Surface Energy Of Pis Copolymer, And Its Polar Component Is Leveled Off. The Dependence Of Peel Strength Of Adhesive Joint Pis Copolymer-Epoxy Versus Polar Fraction Of The Copolymer Shows, That The Steepest Gradient Is Reached At 15 Wt.% Of Siloxane Pis Block Copolymer, And Then It Is Leveled Off. This Relation Allows The Determination Of The Non-Linear Relationship Between Adhesion Properties Of Pis Block Copolymer And Polar Fraction Of The Copolymer. Acknowledgement This Contribution Was Supported By Project No. 26220220091 By The "Research & Development Operational Program" Funded By The Erdf, And As A Part Of The Project „Application Of Knowledge-Based Methods In Designing Manufacturing Systems And Materials", Project Mesrssr No. 3933/2010-11, And Project Vega 2/0185/10.