A “baroplastic” polymer is defined as a material that could be processed at low temperature under medium pressure, which is quite different from conventionally used polymer processing at high temperature and high pressure. We found that polystyrene-block-poly(n-pentylmethacrylate) copolymer (PS-b-PnPMA) showed excellent baroplasticity. Namely, this block copolymer was well-shaped into the desired form by compression molding even at 90 oC and 50 bar. On the other hand, even when much larger pressure of 1000 bar and higher temperature of 120 oC was employed for the compression molding of PS-block-poly(ethylene-co-butylene)-block-PS, we could not shape SEBS into the desired form at this processing condition. By using this block copolymer, we could fabricate ultrahigh density array of nanopatterns on thin film using an atomic force microscope (AFM) tip at room temperature. Unlike conventionally used nanolithographic methods, this approach uses pressure-driven microphase transition by AFM tip without heating. Cross-sectional transmission electron microscopy image clearly showed that nanopatterns were fabricated through the microphase transition from lamellar microdomains to the disordered state by indentation of an AFM tip. The pressure-based phase-change materials at room temperature would be used for next-generation ultrahigh density data storage media. Also, I will present a conceptually new approach to produce highly asymmetric lamellar nanopatterns by the use of binary blends of block copolymers whose components are capable of the hydrogen bonding. To illustrate the impact upon potential lithographic applications, the strategy was transferred to thin film morphologies.